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Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

ablation laser spectrometer  

E-Print Network [OSTI]

ablation laser mass spectrometer molecular beam REMPI laser NREL has designed and developed a combined laser ablation/ pulsed sample introduction/mass spectrometry platform that integrates pyrolysis and/or laser ablation with resonance- enhanced multiphoton ionization (REMPI) time-of-flight mass

2

Single Particle Laser Ablation | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Single Particle Laser Ablation Single Particle Laser Ablation Leads No leads are available at this time. Effect of Solar Radiation on the Optical Properties and Molecular...

3

EMSL - Single Particle Laser Ablation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

single-particle-laser-ablation en Effect of Solar Radiation on the Optical Properties and Molecular Composition of Laboratory Proxies of Atmospheric Brown Carbon http:...

4

Laser ablation based fuel ignition  

DOE Patents [OSTI]

There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition.

Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

1998-01-01T23:59:59.000Z

5

Laser ablation based fuel ignition  

DOE Patents [OSTI]

There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition. 3 figs.

Early, J.W.; Lester, C.S.

1998-06-23T23:59:59.000Z

6

Laser ablation in analytical chemistry - A review  

SciTech Connect (OSTI)

Laser ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser ablation refers to the process in which an intense burst of energy delivered by a short laser pulse is used to sample (remove a portion of) a material. The advantages of laser ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize laser ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.

Russo, Richard E.; Mao, Xianglei; Liu, Haichen; Gonzalez, Jhanis; Mao, Samuel S.

2001-10-10T23:59:59.000Z

7

Laser ablated hard coating for microtools  

DOE Patents [OSTI]

Wear-resistant coatings composed of laser ablated hard carbon films, are deposited by pulsed laser ablation using visible light, on instruments such as microscope tips and micro-surgical tools. Hard carbon, known as diamond-like carbon (DLC), films produced by pulsed laser ablation using visible light enhances the abrasion resistance, wear characteristics, and lifetimes of small tools or instruments, such as small, sharp silicon tips used in atomic probe microscopy without significantly affecting the sharpness or size of these devices. For example, a 10-20 nm layer of diamond-like carbon on a standard silicon atomic force microscope (AFM) tip, enables the useful operating life of the tip to be increased by at least twofold. Moreover, the low inherent friction coefficient of the DLC coating leads to higher resolution for AFM tips operating in the contact mode.

McLean, II, William (Oakland, CA); Balooch, Mehdi (Berkeley, CA); Siekhaus, Wigbert J. (Berkeley, CA)

1998-05-05T23:59:59.000Z

8

Laser ablated hard coating for microtools  

DOE Patents [OSTI]

Wear-resistant coatings composed of laser ablated hard carbon films, are deposited by pulsed laser ablation using visible light, on instruments such as microscope tips and micro-surgical tools. Hard carbon, known as diamond-like carbon (DLC), films produced by pulsed laser ablation using visible light enhances the abrasion resistance, wear characteristics, and lifetimes of small tools or instruments, such as small, sharp silicon tips used in atomic probe microscopy without significantly affecting the sharpness or size of these devices. For example, a 10--20 nm layer of diamond-like carbon on a standard silicon atomic force microscope (AFM) tip, enables the useful operating life of the tip to be increased by at least twofold. Moreover, the low inherent friction coefficient of the DLC coating leads to higher resolution for AFM tips operating in the contact mode. 12 figs.

McLean, W. II; Balooch, M.; Siekhaus, W.J.

1998-05-05T23:59:59.000Z

9

Subcellular analysis by laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

2014-12-02T23:59:59.000Z

10

Solar cell contact formation using laser ablation  

DOE Patents [OSTI]

The formation of solar cell contacts using a laser is described. A method of fabricating a back-contact solar cell includes forming a poly-crystalline material layer above a single-crystalline substrate. The method also includes forming a dielectric material stack above the poly-crystalline material layer. The method also includes forming, by laser ablation, a plurality of contacts holes in the dielectric material stack, each of the contact holes exposing a portion of the poly-crystalline material layer; and forming conductive contacts in the plurality of contact holes.

Harley, Gabriel; Smith, David; Cousins, Peter

2012-12-04T23:59:59.000Z

11

Solar cell contact formation using laser ablation  

DOE Patents [OSTI]

The formation of solar cell contacts using a laser is described. A method of fabricating a back-contact solar cell includes forming a poly-crystalline material layer above a single-crystalline substrate. The method also includes forming a dielectric material stack above the poly-crystalline material layer. The method also includes forming, by laser ablation, a plurality of contacts holes in the dielectric material stack, each of the contact holes exposing a portion of the poly-crystalline materiat layer; and forming conductive contacts in the plurality of contact holes.

Harley, Gabriel; Smith, David D.; Cousins, Peter John

2014-07-22T23:59:59.000Z

12

E-Print Network 3.0 - assisted laser ablation Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

representation of the polymer structure, which permits the study of laser ablation, degradation... . Introduction Ablation of polymers and biological tissues by far-UV lasers...

13

E-Print Network 3.0 - aluminium laser ablation Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

laser ablation Search Powered by Explorit Topic List Advanced Search Sample search results for: aluminium laser ablation Page: << < 1 2 3 4 5 > >> 1 Available online at...

14

Laser Ablation Synthesis and Optical Characterization of Silicon Carbide Nanowires  

E-Print Network [OSTI]

Laser Ablation Synthesis and Optical Characterization of Silicon Carbide Nanowires Wensheng Shi Kong, SAR, China Silicon carbide (SiC) nanowires were synthesized at 900°C by the laser ablation and composite nanostructures,4 have been fabricated by this technique. Silicon carbide (SiC) is a wide

Zheng, Yufeng

15

Femtosecond Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics  

E-Print Network [OSTI]

Femtosecond Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics A thesis presented Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics Eric Mazur Brian R. Tull Abstract irradiated surface layer to the grain boundaries. #12;iv Lastly, we measure the photovoltaic properties

Mazur, Eric

16

Laser ablation loading of a surface-electrode ion trap  

E-Print Network [OSTI]

We demonstrate loading by laser ablation of $^{88}$Sr$^+$ ions into a mm-scale surface-electrode ion trap. The laser used for ablation is a pulsed, frequency-tripled Nd:YAG with pulse energies of 1-10 mJ and durations of 3-5 ns. An additional laser is not required to photoionize the ablated material. The efficiency and lifetime of several candidate materials for the laser ablation target are characterized by measuring the trapped ion fluorescence signal for a number of consecutive loads. Additionally, laser ablation is used to load traps with a trap depth (40 meV) below where electron impact ionization loading is typically successful ($\\gtrsim$ 500 meV).

David R. Leibrandt; Robert J. Clark; Jaroslaw Labaziewicz; Paul Antohi; Waseem Bakr; Kenneth R. Brown; Isaac L. Chuang

2007-06-22T23:59:59.000Z

17

Femtosecond laser ablation of brass in air and liquid media  

SciTech Connect (OSTI)

Laser ablation of brass in air, water, and ethanol was investigated using a femtosecond laser system operating at a wavelength of 785 nm and a pulse width less than 130 fs. Scanning electron and optical microscopy were used to study the efficiency and quality of laser ablation in the three ablation media at two different ablation modes. With a liquid layer thickness of 3 mm above the target, ablation rate was found to be higher in water and ethanol than in air. Ablation under water and ethanol showed cleaner surfaces and less debris re-deposition compared to ablation in air. In addition to spherical particles that are normally formed from re-solidified molten material, micro-scale particles with varying morphologies were observed scattered in the ablated structures (craters and grooves) when ablation was conducted under water. The presence of such particles indicates the presence of a non-thermal ablation mechanism that becomes more apparent when ablation is conducted under water.

Shaheen, M. E. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada) [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Physics, Faculty of Sciences, Tanta University, Tanta (Egypt); Gagnon, J. E.; Fryer, B. J. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada) [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

2013-06-07T23:59:59.000Z

18

Plume collimation for laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

Vertes, Akos; Stolee, Jessica A.

2014-09-09T23:59:59.000Z

19

Revisiting the interplay between ablation, collisional, and radiative processes during ns-laser ablation  

SciTech Connect (OSTI)

A study of ns-laser ablation is presented, which focuses on the transient behavior of the physical processes that act in and above a copper sample. A dimensionless multiphase collisional radiative model describes the interplay between the ablation, collisional, and radiative mechanisms. Calculations are done for a 6 ns-Nd:YAG laser pulse operating at 532 nm and fluences up to 15 J/cm{sup 2}. Temporal intensity profiles as well as transmissivities are in good agreement with experimental results. It is found that volumetric ablation mechanisms and photo-processes both play an essential role in the onset of ns-laser induced breakdown.

Autrique, D. [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany) [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany); Department of Chemistry, University of Antwerp, 2610 Wilrijk (Belgium); Gornushkin, I. [Federal Institute for Materials Research and Testing - BAM, 12489 Berlin (Germany)] [Federal Institute for Materials Research and Testing - BAM, 12489 Berlin (Germany); Alexiades, V. [Department of Mathematics, University of Tennessee, Knoxville, Tennessee 37996-1320 (United States)] [Department of Mathematics, University of Tennessee, Knoxville, Tennessee 37996-1320 (United States); Chen, Z.; Bogaerts, A. [Department of Chemistry, University of Antwerp, 2610 Wilrijk (Belgium)] [Department of Chemistry, University of Antwerp, 2610 Wilrijk (Belgium); Rethfeld, B. [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany)] [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany)

2013-10-21T23:59:59.000Z

20

Laser ablation system, and method of decontaminating surfaces  

DOE Patents [OSTI]

A laser ablation system comprising a laser head providing a laser output; a flexible fiber optic cable optically coupled to the laser output and transmitting laser light; an output optics assembly including a nozzle through which laser light passes; an exhaust tube in communication with the nozzle; and a blower generating a vacuum on the exhaust tube. A method of decontaminating a surface comprising the following steps: providing an acousto-optic, Q-switched Nd:YAG laser light ablation system having a fiber optically coupled output optics assembly; and operating the laser light ablation system to produce an irradiance greater than 1.times.10.sup.7 W/cm.sup.2, and a pulse width between 80 and 170 ns.

Ferguson, Russell L. (Idaho Falls, ID); Edelson, Martin C. (Ames, IA); Pang, Ho-ming (Ames, IA)

1998-07-14T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Surface Decontamination Using Laser Ablation Process - 12032  

SciTech Connect (OSTI)

A new decontamination method has been investigated and used during two demonstration stages by the Clean-Up Business Unit of AREVA. This new method is based on the use of a Laser beam to remove the contaminants present on a base metal surface. In this paper will be presented the type of Laser used during those tests but also information regarding the efficiency obtained on non-contaminated (simulated contamination) and contaminated samples (from the CEA and La Hague facilities). Regarding the contaminated samples, in the first case, the contamination was a quite thick oxide layer. In the second case, most of the contamination was trapped in dust and thin grease layer. Some information such as scanning electron microscopy (SEM), X-Ray scattering spectroscopy and decontamination factors (DF) will be provided in this paper. Laser technology appears to be an interesting one for the future of the D and D applications. As shown in this paper, the results in terms of efficiency are really promising and in many cases, higher than those obtained with conventional techniques. One of the most important advantages is that all those results have been obtained with no generation of secondary wastes such as abrasives, chemicals, or disks... Moreover, as mentioned in introduction, the Laser ablation process can be defined as a 'dry' process. This technology does not produce any liquid waste (as it can be the case with chemical process or HP water process...). Finally, the addition of a vacuum system allows to trap the contamination onto filters and thus avoiding any dissemination in the room where the process takes place. The next step is going to be a commercial use in 2012 in one of the La Hague buildings. (authors)

Moggia, Fabrice; Lecardonnel, Xavier; Damerval, Frederique [AREVA, Back End Business Group, Clean Up Business Unit (France)

2012-07-01T23:59:59.000Z

22

Laser ablation for the synthesis of carbon nanotubes  

DOE Patents [OSTI]

Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces and output above about 50 watts/cm.sup.2 at a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of "side pumped", preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.

Holloway, Brian C; Eklund, Peter C; Smith, Michael W; Jordan, Kevin C; Shinn, Michelle

2012-11-27T23:59:59.000Z

23

Laser ablation for the synthesis of carbon nanotubes  

DOE Patents [OSTI]

Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces an output above about 50 watts/cm2 at a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of "side pumped", preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.

Holloway, Brian C.; Eklund, Peter C.; Smith, Michael W.; Jordan, Kevin C.; Shinn, Michelle

2010-04-06T23:59:59.000Z

24

Laser ablation of iron: A comparison between femtosecond and picosecond laser pulses  

SciTech Connect (OSTI)

In this study, a comparison between femtosecond (fs) and picosecond (ps) laser ablation of electrolytic iron was carried out in ambient air. Experiments were conducted using a Ti:sapphire laser that emits radiation at 785 nm and at pulse widths of 110 ps and 130 fs, before and after pulse compression, respectively. Ablation rates were calculated from the depth of craters produced by multiple laser pulses incident normally to the target surface. Optical and scanning electron microscopy showed that picosecond laser pulses create craters that are deeper than those created by the same number of femtosecond laser pulses at the same fluence. Most of the ablated material was ejected from the ablation site in the form of large particles (few microns in size) in the case of picosecond laser ablation, while small particles (few hundred nanometers) were produced in femtosecond laser ablation. Thermal effects were apparent at high fluence in both femtosecond and picosecond laser ablation, but were less prevalent at low fluence, closer to the ablation threshold of the material. The quality of craters produced by femtosecond laser ablation at low fluence is better than those created at high fluence or using picosecond laser pulses.

Shaheen, M. E. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada) [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Physics, Faculty of Sciences, Tanta University, Tanta (Egypt); Gagnon, J. E.; Fryer, B. J. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada) [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

2013-08-28T23:59:59.000Z

25

E-Print Network 3.0 - arf laser ablation Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

laser ablation Search Powered by Explorit Topic List Advanced Search Sample search results for: arf laser ablation Page: << < 1 2 3 4 5 > >> 1 Lasers in Surgery and Medicine...

26

Nanoscale patterning of graphene through femtosecond laser ablation  

SciTech Connect (OSTI)

We report on nanometer-scale patterning of single layer graphene on SiO{sub 2}/Si substrate through femtosecond laser ablation. The pulse fluence is adjusted around the single-pulse ablation threshold of graphene. It is shown that, even though both SiO{sub 2} and Si have more absorption in the linear regime compared to graphene, the substrate can be kept intact during the process. This is achieved by scanning the sample under laser illumination at speeds yielding a few numbers of overlapping pulses at a certain point, thereby effectively shielding the substrate. By adjusting laser fluence and translation speed, 400?nm wide ablation channels could be achieved over 100??m length. Raster scanning of the sample yields well-ordered periodic structures, provided that sufficient gap is left between channels. Nanoscale patterning of graphene without substrate damage is verified with Scanning Electron Microscope and Raman studies.

Sahin, R.; Akturk, S., E-mail: selcuk.akturk@itu.edu.tr [Department of Physics, Istanbul Technical University, Maslak 34469, Istanbul (Turkey); Simsek, E. [Electrical and Computer Engineering, The George Washington University, Washington, DC 20052 (United States)

2014-02-03T23:59:59.000Z

27

Trace contaminant determination in fish scale by laser ablation technique  

SciTech Connect (OSTI)

Laser ablation on rings of fish scale has been used to analyze the historical accumulation of polychlorinated biphenyls (PCB) in striped bass in the Watts Bar Reservoir. Rings on a fish scale grow in a pattern that forms a record of the fish`s chemical intake. In conjunction with the migration patterns of fish monitored by ecologists, relative PCB concentrations in the seasonal rings of fish scale can be used to study the PCB distribution in the reservoir. In this study, a tightly-focused laser beam from a XeCl excimer laser was used to ablate and ionize a small portion of a fish scale placed in a vacuum chamber. The ions were identified and quantified by a time-of-flight mass spectrometer. Studies of this type can provide valuable information for the Department of Energy`s (DOE) off-site clean-up efforts as well as identifying the impacts of other sources to local aquatic populations.

Lee, I.; Coutant, C.C.; Arakawa, E.T.

1993-06-01T23:59:59.000Z

28

Pico- and nanosecond laser ablation of mixed tungsten / aluminium films  

E-Print Network [OSTI]

In order to extend the investigation of laser-assisted cleaning of ITER-relevant first mirror materials to the picosecond regime, a commercial laser system delivering 10 picosecond pulses at 355 nm at a frequency of up to 1 MHz has been used to investigate the ablation of mixed aluminium (oxide) / tungsten (oxide) layers deposited on poly- and nanocrystalline molybdenum as well as nanocrystalline rhodium mirrors. Characterization before and after cleaning using scanning electron microscopy (SEM) and spectrophotometry shows heavy dust formation, resulting in a degradation of the reflectivity. Cleaning using a 5 nanosecond pulses at 350 and 532 nm, on the other hand, proved very promising. The structure of the film remnants suggests that in this case buckling was the underlying removal mechanism rather than ablation. Repeated coating and cleaning using nanosecond pulses is demonstrated.

Wisse, M; Steiner, R; Mathys, D; Stumpp, A; Joanny, M; Travere, J M; Meyer, E

2014-01-01T23:59:59.000Z

29

Growth of epitaxial thin films by pulsed laser ablation  

SciTech Connect (OSTI)

High-quality, high-temperature superconductor (HTSc) films can be grown by the pulsed laser ablation (PLA) process. This article provides a detailed introduction to the advantages and curent limitations of PLA for epitaxial film growth. Emphasis is placed on experimental methods and on exploitation of PLA to control epitaxial growth at either the unit cell or the atomic-layer level. Examples are taken from recent HTSc film growth. 33 figs, 127 refs. (DLC)

Lowndes, D.H.

1992-10-01T23:59:59.000Z

30

Growth of epitaxial thin films by pulsed laser ablation  

SciTech Connect (OSTI)

High-quality, high-temperature superconductor (HTSc) films can be grown by the pulsed laser ablation (PLA) process. This article provides a detailed introduction to the advantages and curent limitations of PLA for epitaxial film growth. Emphasis is placed on experimental methods and on exploitation of PLA to control epitaxial growth at either the unit cell or the atomic-layer level. Examples are taken from recent HTSc film growth. 33 figs, 127 refs. (DLC)

Lowndes, D.H.

1992-01-01T23:59:59.000Z

31

Properties of zirconia thin films deposited by laser ablation  

SciTech Connect (OSTI)

Zirconia thin films have been deposited by laser ablation of a ceramic ZrO{sub 2} target in vacuum or in oxygen background at 0.01 mbar. The laser beam generated by an ArF laser (?=193 nm, ?=40 Hz) has been focalized on the target through a spherical lens at an incident angle of 45°. The laser fluence has been established to a value from 2.0 to 3.4 Jcm{sup ?2}. A silicon (100) substrate has been placed parallel to the target, at a distance of 4 cm, and subsequently has been heated to temperatures ranging between 300 °C and 600 °C. Thin films morphology has been characterized by atomic force microscopy and secondary ion mass spectrometry. Biocompatibility of these thin films has been assessed by studying the cell attachment of L929 mouse fibroblasts.

Cancea, V. N. [Department of Physics, University of Craiova, Craiova 200585 (Romania); Filipescu, M.; Colceag, D.; Dinescu, M. [Department of Lasers, National Institute for Laser, Plasma and Radiation Physics, Magurele 077125 (Romania); Mustaciosu, C. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Magurele, Bucharest (Romania)

2013-11-13T23:59:59.000Z

32

Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos (Reston, VA); Nemes, Peter (Silver Spring, MD)

2011-06-21T23:59:59.000Z

33

Laser ablation electrospray ionization (LAESI) for atmospheric pressure, In vivo, and imaging mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation (LA) with electrospray ionization (ESI).

Vertes, Akos (Reston, VA); Nemes, Peter (Silver Spring, MD)

2011-11-29T23:59:59.000Z

34

Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos; Nemes, Peter

2014-08-19T23:59:59.000Z

35

E-Print Network 3.0 - ablative fractional lasers Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

www.sciencedirect.com SiliconPV: 17-20 April 2011, Freiburg, Germany Summary: selective laser ablation for local contacts to thin emitters Felix Haasea *, Enrique Garralaga...

36

Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos; Nemes, Peter

2013-07-16T23:59:59.000Z

37

Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos; Nemes, Peter

2013-07-16T23:59:59.000Z

38

Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos; Nemes, Peter

2012-10-30T23:59:59.000Z

39

A study of particle generation during laser ablation withapplications  

SciTech Connect (OSTI)

A study has been made of the generation of particles during laser ablation and has included size distribution measurements and observation of the formation processes. The particle size distribution with respect to different laser parameters was obtained in-line using a differential mobility analyzer (DMA) and a particle counter. The experimental results show that the particle size varies with laser energy, laser pulsewidth, ambient gas flow rate and sample properties. The results serve as a basis for controlling the size of nanoparticles generated by laser ablation. Laser shadowgraph imaging was used to study mass ejection processes and mechanisms. At higher laser irradiance, some particles were ejected in the liquid and even in the solid phase. Time-resolved images show the propagation of the shockwaves: external shockwaves propagate outward and decelerate, and internal shockwaves reflect back and forth between the gas contact surface and the sample surface. The internal shockwave is proposed to cause the ejection of liquid particles when the internal shockwave strikes the liquid molten layer. A simulation based on vapor plume expansion was carried out and provides satisfactory agreement with experimental results. Different material properties result in different particle ejection behavior:particle ejection for most materials including metals result in a conically shaped envelope for the ejected material while ejection for silicon resembles a liquid jet. The difference in density change when the materials melt was proposed to be an important factor in the different ejection behavior. The characteristics of particles generated by laser ablation have a strong influence on the chemical analysis of the irradiated sample. Large particles are more difficult to completely vaporize and ionize, and induced preferential vaporization causes fractionation (i.e. a detected chemical composition that differs from the sample material). Large particles also result in spikes in measurements using inductively coupled plasma mass spectrometry (ICP-MS) which result in errors. Three different methods were employed to study the effects of particle size on chemical analysis: generating smaller particles utilizing a fs laser, filtering out larger particles with a cascade impactor and altering the size distribution by using a second pulse to fracture particles generated from the first pulse. It was found that the chemical composition of the particles varies with particle size. The variation of the composition with respect to particle size was analyzed and it was proposed that it was related to the vapor formed particles condensing on larger ejected liquid droplets.

Liu, Chunyi

2005-08-12T23:59:59.000Z

40

Laser ablative synthesis of carbon nanotubes  

DOE Patents [OSTI]

An improved method for the production of single walled carbon nanotubes that utilizes an RF-induction heated side-pumped synthesis chamber for the production of such. Such a method, while capable of producing large volumes of carbon nanotubes, concurrently permits the use of a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization. The method of the present invention utilizes a free electron laser operating at high average and peak fluence to illuminate a rotating and translating graphite/catalyst target to obtain high yields of SWNTs without the use of a vacuum chamber.

Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA); Park, Cheol (Yorktown, VA)

2010-03-02T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Testing of concrete by laser ablation  

DOE Patents [OSTI]

A method of testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed.

Flesher, Dann J. (Benton City, WA); Becker, David L. (Kennewick, WA); Beem, William L. (Kennewick, WA); Berry, Tommy C. (Kennewick, WA); Cannon, N. Scott (Kennewick, WA)

1997-01-01T23:59:59.000Z

42

Testing of concrete by laser ablation  

DOE Patents [OSTI]

A method is disclosed for testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed. 1 fig.

Flesher, D.J.; Becker, D.L.; Beem, W.L.; Berry, T.C.; Cannon, N.S.

1997-01-07T23:59:59.000Z

43

Multidiagnostic analysis of ultrafast laser ablation of metals with pulse pair irradiation  

SciTech Connect (OSTI)

Copper targets are irradiated in the ablation regime by pairs of equal, time-delayed collinear laser pulses separated on a timescale going from {approx_equal}2 ps to {approx_equal}2 ns. The ablation plume is characterized by ion probe diagnostic, fast imaging, and temporally and spatially resolved optical emission spectroscopy. The variation in the ablation efficiency with the delay between the pulses is analyzed by measuring the ablation crater profile with a contact profilometer. The second laser pulse modifies the characteristics of the plasma plume produced by the first pulse and the ablation efficiency. The different mechanisms involved in double pulse ultrafast laser ablation are identified and discussed. The experimental findings are interpreted in the frame of a simple model of the interaction of the second pulse with the nascent ablation plume produced by the first pulse. This model yields consistent and quantitative agreement with the experimental findings predicting the observed experimental trends of the ablation depth reduction and ion yield increase with the delay between the pulses, as well as the characteristic timescale of the observed changes. The possibility of controlling the characteristics of the plumes produced during ultrafast laser ablation via an efficient coupling of the energy of the second pulse to the various ablation components produced by the first pulse is of particular interest in ultrafast pulsed laser deposition and microprobe analyses of materials.

Amoruso, S.; Bruzzese, R. [Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); CNR-SPIN, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Wang, X. [CNR-SPIN, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); O'Connell, G.; Lunney, J. G. [School of Physics, Trinity College-Dublin, Dublin 2 (Ireland)

2010-12-01T23:59:59.000Z

44

Femtosecond laser ablation of indium tin-oxide narrow grooves for thin film solar cells  

E-Print Network [OSTI]

Femtosecond laser ablation of indium tin-oxide narrow grooves for thin film solar cells Qiumei Bian in the fabrication and assembly of thin film solar cells. Using a femtosecond (fs) laser, we selectively removed a unique scheme to ablate the indium tin-oxide layer for the fabrication of thin film solar cells

Van Stryland, Eric

45

Electrical and optical properties of diamond-like carbon films deposited by pulsed laser ablation  

E-Print Network [OSTI]

films, which make them more useful than polycrystalline diamond films for many applications. For exampleElectrical and optical properties of diamond-like carbon films deposited by pulsed laser ablation K e i n f o Available online 11 March 2010 Keyword: Pulsed laser ablation Diamond-like carbon films

Bristol, University of

46

High-throughput metal nanoparticle catalysis by pulsed laser ablation Selim Senkan a,*, Michael Kahn a  

E-Print Network [OSTI]

High-throughput metal nanoparticle catalysis by pulsed laser ablation Selim Senkan a,*, Michael online 18 July 2006 Abstract A high-throughput pulsed laser ablation (HT-PLA) system was developed-TEM) and energy dispersive X-ray (EDX) spectroscopy, respectively. The supported nanoparticles created by HT

Senkan, Selim M.

47

Nanoscale patterning of graphene through femtosecond laser ablation R. Sahin, E. Simsek, and S. Akturk  

E-Print Network [OSTI]

Nanoscale patterning of graphene through femtosecond laser ablation R. Sahin, E. Simsek, and S.164.158.129 On: Mon, 10 Feb 2014 15:01:27 #12;Nanoscale patterning of graphene through femtosecond laser ablation 2014) We report on nanometer-scale patterning of single layer graphene on SiO2/Si substrate through

Simsek, Ergun

48

Laser ablated copper plasmas in liquid and gas ambient  

SciTech Connect (OSTI)

The dynamics of copper ablated plasma plumes generated using laser ablation of copper targets in both liquid (de-ionized water) and gas (air) ambients is reported. Using time and space resolved visible emission spectroscopy (450-650 nm), the plasma plumes parameters are investigated. The electron density (n{sub e}) determined using Stark broadening of the Cu I (3d{sup 10}4d{sup 1} {sup 2}D{sub 3/2}-3d{sup 10}4p{sup 1} {sup 2}P{sub 3/2} at 521.8 nm) line is estimated and compared for both plasma plumes. The electron temperature (T{sub e}) was estimated using the relative line emission intensities of the neutral copper transitions. Field emission scanning electron microscopy and energy dispersive x-ray spectral analysis of the ablated copper surface indicated abundance of spherical nanoparticles in liquid while those in air are amalgamates of irregular shapes. The nanoparticles suspended in the confining liquid form aggregates and exhibit a surface plasmon resonance at ?590 nm.

Kumar, Bhupesh; Thareja, Raj K. [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)] [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

2013-05-15T23:59:59.000Z

49

Process and structures for fabrication of solar cells with laser ablation steps to form contact holes  

DOE Patents [OSTI]

Contact holes of solar cells are formed by laser ablation to accomodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thickness.

Harley, Gabriel; Smith, David D; Dennis, Tim; Waldhauer, Ann; Kim, Taeseok; Cousins, Peter John

2013-11-19T23:59:59.000Z

50

RAPID COMMUNICATION Quantifying the quality of femtosecond laser ablation of graphene  

E-Print Network [OSTI]

RAPID COMMUNICATION Quantifying the quality of femtosecond laser ablation of graphene Ramazan Sahin abla- tion quality and ablation size is experimentally studied on graphene-coated silicon Introduction Graphene micro- and nano-structures are considered potential building blocks for future opto

Simsek, Ergun

51

Infrared nanosecond laser-metal ablation in atmosphere: Initial plasma during laser pulse and further expansion  

SciTech Connect (OSTI)

We have investigated the dynamics of the nanosecond laser ablated plasma within and after the laser pulse irradiation using fast photography. A 1064 nm, 15 ns laser beam was focused onto a target made from various materials with an energy density in the order of J/mm{sup 2} in atmosphere. The plasma dynamics during the nanosecond laser pulse were observed, which could be divided into three stages: fast expansion, division into the primary plasma and the front plasma, and stagnation. After the laser terminated, a critical moment when the primary plasma expansion transited from the shock model to the drag model was resolved, and this phenomenon could be understood in terms of interactions between the primary and the front plasmas.

Wu, Jian; Wei, Wenfu; Li, Xingwen; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)

2013-04-22T23:59:59.000Z

52

Fully Automated Laser Ablation Liquid Capture Sample Analysis using NanoElectrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

RATIONALE: Laser ablation provides for the possibility of sampling a large variety of surfaces with high spatial resolution. This type of sampling when employed in conjunction with liquid capture followed by nanoelectrospray ionization provides the opportunity for sensitive and prolonged interrogation of samples by mass spectrometry as well as the ability to analyze surfaces not amenable to direct liquid extraction. METHODS: A fully automated, reflection geometry, laser ablation liquid capture spot sampling system was achieved by incorporating appropriate laser fiber optics and a focusing lens into a commercially available, liquid extraction surface analysis (LESA ) ready Advion TriVersa NanoMate system. RESULTS: Under optimized conditions about 10% of laser ablated material could be captured in a droplet positioned vertically over the ablation region using the NanoMate robot controlled pipette. The sampling spot size area with this laser ablation liquid capture surface analysis (LA/LCSA) mode of operation (typically about 120 m x 160 m) was approximately 50 times smaller than that achievable by direct liquid extraction using LESA (ca. 1 mm diameter liquid extraction spot). The set-up was successfully applied for the analysis of ink on glass and paper as well as the endogenous components in Alstroemeria Yellow King flower petals. In a second mode of operation with a comparable sampling spot size, termed laser ablation/LESA , the laser system was used to drill through, penetrate, or otherwise expose material beneath a solvent resistant surface. Once drilled, LESA was effective in sampling soluble material exposed at that location on the surface. CONCLUSIONS: Incorporating the capability for different laser ablation liquid capture spot sampling modes of operation into a LESA ready Advion TriVersa NanoMate enhanced the spot sampling spatial resolution of this device and broadened the surface types amenable to analysis to include absorbent and solvent resistant materials.

Lorenz, Matthias [ORNL] [ORNL; Ovchinnikova, Olga S [ORNL] [ORNL; Van Berkel, Gary J [ORNL] [ORNL

2014-01-01T23:59:59.000Z

53

Dynamics of femto-and nanosecond laser ablation plumes investigated using optical emission spectroscopy  

E-Print Network [OSTI]

. Plasma formation occurs when a high powered pulsed laser is focused onto a target such that the energy, such as pulse duration, energy, and wave- length; along with the target properties and surrounding conditions,10 ion beams11 of various charge states, laser-ablation inductively coupled-plasma mass-spectrometry (LA

Harilal, S. S.

54

Internal structure and expansion dynamics of laser ablation plumes into ambient gases  

E-Print Network [OSTI]

Internal structure and expansion dynamics of laser ablation plumes into ambient gases S. S. Harilal 13 December 2002 The effect of ambient gas on the expansion dynamics of the plasma generated by laser together with time resolved emission diagnostics, a triple structure of the plume was observed

Harilal, S. S.

55

Femtosecond laser ablation of dielectric materials in the optical breakdown regime: Expansion of a transparent shell  

SciTech Connect (OSTI)

Phase transition pathways of matter upon ablation with ultrashort laser pulses have been considered to be understood long-since for metals and semiconductors. We provide evidence that also certain dielectrics follow the same pathway, even at high pulse energies triggering optical breakdown. Employing femtosecond microscopy, we observe a characteristic ring pattern within the ablating region that dynamically changes for increasing time delays between pump and probe pulse. These transient Newton rings are related to optical interference of the probe beam reflected at the front surface of the ablating layer with the reflection at the interface of the non-ablating substrate. Analysis of the ring structure shows that the ablation mechanism is initiated by a rarefaction wave leading within a few tens of picoseconds to the formation of a transparent thin shell of reduced density and refractive index, featuring optically sharp interfaces. The shell expands and eventually detaches from the solid material at delays of the order of 100 ps.

Garcia-Lechuga, M.; Siegel, J., E-mail: j.siegel@io.cfmac.csic.es; Hernandez-Rueda, J.; Solis, J. [Laser Processing Group, Instituto de Optica, Serrano 121, 28006 Madrid (Spain)

2014-09-15T23:59:59.000Z

56

Laser diagnostic experiments on KrF laser ablation plasma-plume dynamics relevant to manufacturing applications  

SciTech Connect (OSTI)

A brief review is given of the potential applications of laser ablation in the automotive and electronics manufacturing industries. Experiments are presented on KrF laser ablation of three materials relevant to manufacturing applications: aluminum metal vs aluminum--nitride (AlN) and alumina (Al[sub 2]O[sub 3]) ceramics. Plasma and neutral-atom diagnostic data are presented from resonant-holographic-interferometry, dye-laser-resonance-absorption photography, and HeNe laser deflection. Data show that plasma electron densities in excess of 10[sup 18] cm[sup [minus]3] exist in the ablation of AlN, with lower densities in Al and Al[sub 2]O[sub 3]. Aluminum neutral and ion expansion velocities are in the range of cm/[mu]s. Ambipolar electric fields are estimated to be 5--50 V/cm.

Gilgenbach, R.M.; Ching, C.H.; Lash, J.S.; Lindley, R.A. (Intense Energy Beam Interaction Laboratory, Nuclear Engineering Department, University of Michigan, Ann Arbor, Michigan 48109-2104 (United States))

1994-05-01T23:59:59.000Z

57

Laser ablation of AlN films grown on sapphire substrate  

SciTech Connect (OSTI)

Ablation threshold for single-crystal AlN semiconductor films grown epitaxially on sapphire substrate using indigenously built hollow cathode plasma deposition source molecular-beam epitaxy technique is investigated for a number of pulses by varying the fluence value of each pulse. Using a KrF excimer laser ({lambda}=248 nm and {tau}=25 ns) as a radiation source, we found that ablation of AlN thin films is a discontinuous process and its onset requires a minimum threshold fluence {approx_equal}1.59 J/cm{sup 2}. The ablation depth is analyzed for different numbers of pulses and for each number as a function of increasing fluence values. The results show that the ablation depth increases linearly with increasing pulse fluence. It is found that the use of a single pulse for ablation at a given value of fluence is more efficient than a large number of pulses at the same value of fluence/pulse. In addition, we investigated the lowest pulse-fluence limit that can sustain ablation on a disordered AlN film surface. We present a theoretical discussion about the laser energy absorption mechanism and also the rate of energy transfer from the conduction-band electrons to lattice phonons which can lead to the ablation of AlN film. It is found that the rate of energy transfer increases linearly with increasing temperature of the electron gas.

Safadi, Mona R.; Thakur, Jagdish S.; Auner, Gregory W. [Department of Biomedical Engineering, Ligon Center of Vision, Wayne State University, Detroit, Michigan 48202 (United States); Department of Electrical and Computer Engineering, Wayne State University, Detroit, Michigan 48202 (United States); Department of Electrical and Computer Engineering, Department of Biomedical Engineering, Ligon Center of Vision, Wayne State University, Detroit, Michigan 48202 (United States)

2005-04-15T23:59:59.000Z

58

Direct femtosecond laser ablation of copper with an optical vortex beam  

SciTech Connect (OSTI)

Laser surface structuring of copper is induced by laser ablation with a femtosecond optical vortex beam generated via spin-to-orbital conversion of the angular momentum of light by using a q-plate. The variation of the produced surface structures is studied as a function of the number of pulses, N, and laser fluence, F. After the first laser pulse (N?=?1), the irradiated surface presents an annular region characterized by a corrugated morphology made by a rather complex network of nanometer-scale ridges, wrinkles, pores, and cavities. Increasing the number of pulses (2?ablated area is gradually decorated by nanoparticles produced during laser ablation. At large number of pulses (200??1000) and a deep crater is formed. The nanostructure variation with the laser fluence, F, also evidences an interesting dependence, with a coarsening of the structure morphology as F increases. Our experimental findings demonstrate that direct femtosecond laser ablation with optical vortex beams produces interesting patterns not achievable by the more standard beams with a Gaussian intensity profile. They also suggest that appropriate tuning of the experimental conditions (F, N) can allow generating micro- and/or nano-structured surface for any specific application.

Anoop, K. K.; Rubano, A.; Marrucci, L.; Bruzzese, R.; Amoruso, S., E-mail: amoruso@na.infn.it [Dipartimento di Fisica, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); CNR-SPIN, UOS Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Fittipaldi, R.; Vecchione, A. [CNR-SPIN, UOS Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (Italy); Wang, X.; Paparo, D. [CNR-SPIN, UOS Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy)

2014-09-21T23:59:59.000Z

59

Using a Fast-Scanning Electrical Nanoparticle Sizer to Characterize Nanoparticles from Laser Ablation  

SciTech Connect (OSTI)

A Fast-Scanning Electrical Nanoparticle Sizer (FSENS) consisting of a Po 210 bipolar charger, a Nano-DMA, and an aerosol electrometer was used to characterize nanoparticles generated by laser ablating the surfaces of cement, chromium-embedded cement, stainless steel, and alumina samples. Different from previous studies, bimodal size distributions, with the nucleation mode having a geometric mean diameter ranging from 5.7-6.6 nm and a geometric standard deviation varying from 1.225-1.379, were observed for all the experimental runs. The curve fitting shows that the bimodal size distribution produced in the laser ablation can be best fitted by a lognormal distribution for the nucleation mode and a Rosin-Rammler distribution for the coagulation mode. At steady state the geometric mean diameter of the coagulation mode was affected by the laser wavelength and target material, but was less influenced by laser energy for a given wavelength. The total particle number concentrations of the two modes appear to be parabolic with respect to the laser fluence. At a given fluence, the stainless-steel sample produced the highest particle number concentration with 532- and 1064-nm lasers; the alumina sample produced the lowest particle number concentration with 266- and 1064-nm lasers. The chromium-embedded cement sample produced fewer particles with 532- and 1064 nm lasers than the pure cement sample. This study also demonstrated that FSENS can provide snapshots of the nanoparticle dynamics during laser ablation in cases of low laser fluence.

Chen, Da-Ren [ORNL; Cheng, Mengdawn [ORNL

2007-01-01T23:59:59.000Z

60

Enhancement of muonium emission rate from silica aerogel with a laser ablated surface  

E-Print Network [OSTI]

Emission of muonium ($\\mu^+e^-$) atoms from a laser-processed aerogel surface into vacuum was studied for the first time. Laser ablation was used to create hole-like regions with diameter of about 270$~\\mu$m in a triangular pattern with hole separation in the range of 300--500$~\\mu$m. The emission probability for the laser-processed aerogel sample is at least eight times higher than for a uniform one.

G. A. Beer; Y. Fujiwara; S. Hirota; K. Ishida; M. Iwasaki; S. Kanda; H. Kawai; N. Kawamura; R. Kitamura; S. Lee; W. Lee G. M. Marshall; T. Mibe; Y. Miyake; S. Okada; K. Olchanski; A. Olin; Y. Oishi; H. Onishi; M. Otani; N. Saito; K. Shimomura; P. Strasser; M. Tabata; D. Tomono; K. Ueno; K. Yokoyama; E. Won

2014-07-31T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Enhancement of muonium emission rate from silica aerogel with a laser ablated surface  

E-Print Network [OSTI]

Emission of muonium ($\\mu^+e^-$) atoms from a laser-processed aerogel surface into vacuum was studied for the first time. Laser ablation was used to create hole-like regions with diameter of about 270$~\\mu$m in a triangular pattern with hole separation in the range of 300--500$~\\mu$m. The emission probability for the laser-processed aerogel sample is at least eight times higher than for a uniform one.

Beer, G A; Hirota, S; Ishida, K; Iwasaki, M; Kanda, S; Kawai, H; Kawamura, N; Kitamura, R; Lee, S; Marshall, W Lee G M; Mibe, T; Miyake, Y; Okada, S; Olchanski, K; Olin, A; Oishi, Y; Onishi, H; Otani, M; Saito, N; Shimomura, K; Strasser, P; Tabata, M; Tomono, D; Ueno, K; Yokoyama, K; Won, E

2014-01-01T23:59:59.000Z

62

Dense strongly coupled plasma in double laser pulse ablation of lithium: Experiment and simulation  

SciTech Connect (OSTI)

In a simple method of low power nano-second double pulsed laser ablation experiment in collinear geometry, formation of high density strongly coupled plasma is demonstrated. Using time-resolved measurements of the Stark broadened line width and line intensity ratio of the emission lines, the density and temperature of the plasma were estimated respectively. In this experiment, it is shown that ions are strongly coupled (ion-ion coupling parameter comes out to be >4). For comparison, both single and double pulsed laser ablations are presented. For the estimated experimental plasma parameters, first principle Langevin dynamics simulation corroborates the existence of a strongly coupled regime.

Kumar, Ajai; Sivakumaran, V.; Ganesh, R.; Joshi, H. C. [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India)] [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India); Ashwin, J. [Weizmann Institute of Science, Rehovot - 76100 (Israel)] [Weizmann Institute of Science, Rehovot - 76100 (Israel)

2013-08-15T23:59:59.000Z

63

New Combined Laser Ablation Platform Determines Cell Wall Chemistry (Fact Sheet)  

SciTech Connect (OSTI)

NREL has designed and developed a combined laser ablation/pulsed sample introduction/mass spectrometry platform that integrates pyrolysis and/or laser ablation with resonance-enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry. Using this apparatus, we can measure the cell wall chemical composition of untreated biomass materials. Understanding the chemical composition of untreated biomass is key to both the biochemical and thermochemical conversion of lignocellulosic biomass to biofuels. In the biochemical conversion process, the new technique provides a better understanding of the chemistry of lignin and will improve accessibility to plant sugars. In thermochemical conversion, the information provided by the new technique may help to reduce the formation of unwanted byproducts during gasification. NREL validated the ability of the system to detect pyrolysis products from plant materials using poplar, a potentially high-impact bioenergy feedstock. In the technique, biomass vapors are produced by laser ablation using the 3rd harmonic of an Nd:YAG laser (355 nm). The resulting vapors are entrained in a free jet expansion of helium, then skimmed and introduced into an ionization region. REMPI is used to ionize the vapors because it is highly sensitive for detecting lignin and aromatic metabolites. The laser ablation method was used to selectively volatilize specific plant tissues and detect lignin-based products from the vapors with enhanced sensitivity. This will allow the determination of lignin distribution in future biomass studies.

Not Available

2011-09-01T23:59:59.000Z

64

Investigation of the effect of water content, thickness and optical properties on laser ablation of biological tissue  

E-Print Network [OSTI]

. Polyacrylamide gel was used as an experimental model for biological tissue in the thickness experiments using the Er:YAG laser. The mass of the gel was measured before and after ablation. The front diameter of ablation was also monitored. The ablation rate... was studied as a function of gel position. By moving the polyacrylamide gel away from the biconvex lens, the beam diameter of the Er:YAG laser was increased. The ablation rate decreased almost exponentially with increasing beam diameter as did the energy...

Vaidyanathan, Varadarajan

1991-01-01T23:59:59.000Z

65

Single-shot and single-spot measurement of laser ablation threshold for carbon nanotubes  

E-Print Network [OSTI]

A simple and convenient procedure for single-shot, single-spot ablation threshold measurement has been developed. It is based on the employment of cylindrical lens to obtain elliptical Gaussian laser spot. The ablated spot chords which are parallel to the minor axis were measured across the spot major axis which is proportional to the fluence cross-section thus providing wide range dependence of damaged spot size versus fluence in one spot measurement. For both conventional and new-developed procedures the ablation threshold for typical Nd:YAG laser parameters (1064 nm, 10 ns) has been measured as 50 mJ/cm2 which is one order of magnitude lower than that for a bulk graphite.

Lednev, Vasily N; Obraztsova, Elena D; Kudryashov, Sergey I; Bunkin, Alexey F

2013-01-01T23:59:59.000Z

66

Experimental scaling law for mass ablation rate from a Sn plasma generated by a 1064 nm laser  

E-Print Network [OSTI]

. INTRODUCTION Laser produced Sn plasma, in its role as an efficient extreme ultraviolet EUV x-ray sourceExperimental scaling law for mass ablation rate from a Sn plasma generated by a 1064 nm laser depth in planar Sn targets irradiated with a pulsed 1064 nm laser was investigated over laser

Najmabadi, Farrokh

67

High-Resolution Optical Coherence Tomography-Guided Laser Ablation of Surgical Tissue1  

E-Print Network [OSTI]

High-Resolution Optical Coherence Tomography-Guided Laser Ablation of Surgical Tissue1 Stephen A Hospital, Boston, Massachusetts 02114 Submitted for publication September 17, 1998 Background. Optical coherence tomography (OCT) is a compact high-speed imaging technology which uses infrared light to acquire

Boppart, Stephen

68

The effect of ultrafast laser wavelength on ablation properties and implications on sample introduction in inductively coupled plasma mass spectrometry  

SciTech Connect (OSTI)

We investigated the role of femtosecond (fs) laser wavelength on laser ablation (LA) and its relation to laser generated aerosol counts and particle distribution, inductively coupled plasma-mass spectrometry (ICP-MS) signal intensity, detection limits, and elemental fractionation. Four different NIST standard reference materials (610, 613, 615, and 616) were ablated using 400 nm and 800 nm fs laser pulses to study the effect of wavelength on laser ablation rate, accuracy, precision, and fractionation. Our results show that the detection limits are lower for 400 nm laser excitation than 800 nm laser excitation at lower laser energies but approximately equal at higher energies. Ablation threshold was also found to be lower for 400 nm than 800 nm laser excitation. Particle size distributions are very similar for 400 nm and 800 nm wavelengths; however, they differ significantly in counts at similar laser fluence levels. This study concludes that 400 nm LA is more beneficial for sample introduction in ICP-MS, particularly when lower laser energies are to be used for ablation.

LaHaye, N. L.; Harilal, S. S.; Diwakar, P. K.; Hassanein, A. [Center for Materials under Extreme Environment, School of Nuclear Engineering Purdue University, West Lafayette, Indiana 47907 (United States); Kulkarni, P. [Centers for Disease Control and Prevention, National Institute of Occupational Safety and Health, Cincinnati, Ohio 45213 (United States)

2013-07-14T23:59:59.000Z

69

Two-dimensional space-resolved emission spectroscopy of laser ablation plasma in water  

SciTech Connect (OSTI)

We developed a method for two-dimensional space-resolved emission spectroscopy of laser-induced plasma in water to investigate the spatial distribution of atomic species involved in the plasma. Using this method, the laser ablation plasma produced on a Cu target in 5 mM NaCl aqueous solution was examined. The emission spectrum varied considerably depending on the detecting position. The temperature and the atomic density ratio N{sub Na}/N{sub Cu} at various detecting positions were evaluated by fitting emission spectra to a theoretical model based on the Boltzmann distribution. We are successful in observing even a small difference between the distributions of the plasma parameters along the directions vertical and horizontal to the surface. The present approach gives direct information for sound understanding of the behavior of laser ablation plasma produced on a solid surface in water.

Matsumoto, Ayumu; Tamura, Ayaka; Fukami, Kazuhiro; Ogata, Yukio H. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Sakka, Tetsuo [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510 (Japan)

2013-02-07T23:59:59.000Z

70

Spatio-temporal mapping of ablated species in ultrafast laser-produced graphite plasmas  

SciTech Connect (OSTI)

We studied the spatial and temporal distributions of ionic, neutral, and molecular species generated by femtosecond laser produced plasma under varying ambient nitrogen gas pressures. Plasmas were generated by irradiating planar graphite targets using 40 fs pulses of 800 nm radiation from a Ti:Sapphire laser. The results show that in the presence of an ambient gas, the molecular species spatial extension and lifetime are directly correlated to the evolution of excited ions. The present studies also provide valuable insights into the evolution history of various species and their excitation during ultrafast laser ablation.

Al-Shboul, K. F.; Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

2012-05-28T23:59:59.000Z

71

Safeguards Verification Measurements using Laser Ablation, Absorbance Ratio Spectrometry in Gaseous Centrifuge Enrichment Plants  

SciTech Connect (OSTI)

Laser Ablation Absorbance Ratio Spectrometry (LAARS) is a new verification measurement technology under development at the US Department of Energy (DOE) Pacific Northwest National Laboratory (PNNL). LAARS uses three lasers to ablate and then measure the relative isotopic abundance of uranium compounds. An ablation laser is tightly focused on uranium-bearing solids, producing a small atomic uranium vapor plume. Two collinear wavelength-tuned spectrometry lasers transit through the plume and the absorbance of U-235 and U-238 isotopes are measured to determine U-235 enrichment. The measurement is independent of chemical form and degree of dilution with nuisance dust and other materials. LAARS has high relative precision and detection limits approaching the femtogram range for U-235. The sample is scanned and assayed point-by-point at rates reaching 1 million measurements/hour, enabling LAARS to detect and analyze uranium in trace samples. The spectrometer is assembled using primarily commercially available components and features a compact design and automated analysis.Two specific gaseous centrifuge enrichment plant (GCEP) applications of the spectrometer are currently under development: 1) LAARS-Environmental Sampling (ES), which collects and analyzes aerosol particles for GCEP misuse detection and 2) LAARS-Destructive Assay (DA), which enables onsite enrichment DA sample collection and analysis for protracted diversion detection. The two applications propose game-changing technological advances in GCEP safeguards verification.

Anheier, Norman C.; Cannon, Bret D.; Kulkarni, Gourihar R.; Munley, John T.; Nelson, Danny A.; Qiao, Hong (Amy) [Amy; Phillips, Jon R.

2012-07-17T23:59:59.000Z

72

Generation of low work function, stable compound thin films by laser ablation  

DOE Patents [OSTI]

Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

Dinh, Long N. (Concord, CA); McLean, II, William (Oakland, CA); Balooch, Mehdi (Berkeley, CA); Fehring, Jr., Edward J. (Dublin, CA); Schildbach, Marcus A. (Livermore, CA)

2001-01-01T23:59:59.000Z

73

Optical time of flight studies of lithium plasma in double pulse laser ablation: Evidence of inverse Bremsstrahlung absorption  

SciTech Connect (OSTI)

The early stage of formation of lithium plasma in a collinear—double pulse laser ablation mode has been studied using optical time of flight (OTOF) spectroscopy as a function of inter-pulse delay time, the distance from the target surface and the fluence of the ablation lasers. The experimental TOF measurements were carried out for lithium neutral (670.8?nm and 610.3?nm), and ionic (548.4?nm and 478.8?nm) lines. These experimental observations have been compared with that for single pulse laser ablation mode. It is found that depending on the fluence and laser pulse shape of the first pre-ablation laser and the second main ablation laser, the plasma plume formation and its characteristic features can be described in terms of plume-plume or laser-plume interaction processes. Moreover, the enhancement in the intensity of Li neutral and ionic lines is observed when the laser-plume interaction is the dominant process. Here, we see the evidence of the role of inverse Bremsstrahlung absorption process in the initial stage of formation of lithium plasma in this case.

Sivakumaran, V.; Joshi, H. C.; Singh, R. K.; Kumar, Ajai, E-mail: ajai@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

2014-06-15T23:59:59.000Z

74

US-Guided Femoral and Sciatic Nerve Blocks for Analgesia During Endovenous Laser Ablation  

SciTech Connect (OSTI)

Endovenous laser ablation may be associated with significant pain when performed under standard local tumescent anesthesia. The purpose of this study was to investigate the efficacy of femoral and sciatic nerve blocks for analgesia during endovenous ablation in patients with lower extremity venous insufficiency. During a 28-month period, ultrasound-guided femoral or sciatic nerve blocks were performed to provide analgesia during endovenous laser ablation in 506 legs and 307 patients. The femoral block (n = 402) was performed at the level of the inguinal ligament, and the sciatic block at the posterior midthigh (n = 124), by injecting a diluted lidocaine solution under ultrasound guidance. After the blocks, endovenous laser ablations and other treatments (phlebectomy or foam sclerotherapy) were performed in the standard fashion. After the procedures, a visual analogue pain scale (1-10) was used for pain assessment. After the blocks, pain scores were 0 or 1 (no pain) in 240 legs, 2 or 3 (uncomfortable) in 225 legs, and 4 or 5 (annoying) in 41 legs. Patients never experienced any pain higher than score 5. The statistical analysis revealed no significant difference between the pain scores of the right leg versus the left leg (p = 0.321) and between the pain scores after the femoral versus sciatic block (p = 0.7). Ultrasound-guided femoral and sciatic nerve blocks may provide considerable reduction of pain during endovenous laser and other treatments, such as ambulatory phlebectomy and foam sclerotherapy. They may make these procedures more comfortable for the patient and easier for the operator.

Yilmaz, Saim, E-mail: ysaim@akdeniz.edu.tr; Ceken, Kagan; Alimoglu, Emel; Sindel, Timur [Akdeniz University School of Medicine, Department of Radiology (Turkey)] [Akdeniz University School of Medicine, Department of Radiology (Turkey)

2013-02-15T23:59:59.000Z

75

Ignition characteristics of laser-ablated aluminum at shock pressures up to 2?GPa  

SciTech Connect (OSTI)

The ignition of aluminum particles under high pressure and temperature conditions is considered. The laser ablation method is used to generate oxide-free aluminum particles exposed to pressures ranging between 0.35 and 2.2?GPa. A continuous wave CO{sub 2} laser radiation heats the surface of the aluminum target until ignition is observed. We confirm ignition by a spectroscopic analysis of AlO vibronic band of 484?nm wavelength, and the radiant temperature is measured with respect to various pressures for estimating the heating energy for ignition. The ignition characteristics of the oxide-free aluminum particles exposed to extremely high pressures are reported.

Lee, Kyung-Cheol; Young Lee, Jae; Yoh, Jack J., E-mail: jjyoh@snu.ac.kr [Department of Mechanical and Aerospace Engineering, Seoul National University, 1 Gwanakro, Gwanakgu, Seoul 151-742 (Korea, Republic of); Taira, Tsubasa [Division of Applied Physics, Hokkaido University, Sapporo (Japan); Mo Koo, Goon [Department of Aerospace Engineering, University of Maryland, College Park, Maryland 20742 (United States)

2014-01-07T23:59:59.000Z

76

Copyright c 2002 Tech Science Press CMES, vol.3, no.5, pp.539-555, 2002 Multiscale Modeling of Laser Ablation: Applications to Nanotechnology  

E-Print Network [OSTI]

of Laser Ablation: Applications to Nanotechnology Leonid V. Zhigilei1 and Avinash M. Dongare 1 Abstract-driven methods in nanotechnology. In this pa- per we discuss two computational schemes developed for simulation, applications of laser ablation have been extended into emerging area of nanotechnology. In particular, laser

Zhigilei, Leonid V.

77

Pulsed laser ablation growth and doping of epitaxial compound semiconductor films  

SciTech Connect (OSTI)

Pulsed laser ablation (PLA) has several characteristics that are potentially attractive for the growth and doping of chemically complex compound semiconductors including (1) stoichiometric (congruent) transfer of composition from target to film, (2) the use of reactive gases to control film composition and/or doping via energetic-beam-induced reactions, and (3) low-temperature nonequilibrium phase formation in the laser-generated plasma ``plume.`` However, the electrical properties of compound semiconductors are far more sensitive to low concentrations of defects than are the oxide metals/ceramics for which PLA has been so successful. Only recently have doped epitaxial compound semiconductor films been grown by PLA. Fundamental studies are being carried out to relate film electrical and microstructural properties to the energy distribution of ablated species, to the temporal evolution of the ablation pulse in ambient gases, and to beam assisted surface and/or gas-phase reactions. In this paper the authors describe results of ex situ Hall effect, high-resolution x-ray diffraction, transmission electron microscopy, and Rutherford backscattering measurements that are being used in combination with in situ RHEED and time-resolved ion probe measurements to evaluate PLA for growth of doped epitaxial compound semiconductor films and heterostructures. Examples are presented and results analyzed for doped II-VI, I-III-VI, and column-III nitride materials grown recently in this and other laboratories.

Lowndes, D.H.; Rouleau, C.M.; Geohegan, D.B.; Budai, J.D.; Poker, D.B. [Oak Ridge National Lab., TN (United States). Solid State Div.; Puretzky, A.A. [Inst. of Spectroscopy, Troitsk (Russian Federation); Strauss, M.A.; Pedraza, A.J.; Park, J.W. [Univ. of Tennessee, Knoxville, TN (United States)

1995-12-01T23:59:59.000Z

78

Dynamics of femtosecond laser absorption of fused silica in the ablation regime  

SciTech Connect (OSTI)

We investigate the ultrafast absorption dynamics of fused silica irradiated by a single 500?fs laser pulse in the context of micromachining applications. A 60-fs-resolution pump-probe experiment that measures the reflectivity and transmissivity of the target under excitation is developed to reveal the evolution of plasma absorption. Above the ablation threshold, an overcritical plasma with highly non-equilibrium conditions is evidenced in a thin layer at the surface. The maximum electron density is reached at a delay of 0.5?ps after the peak of the pump pulse, which is a strong indication of the occurrence of electronic avalanche. The results are further analyzed to determine the actual feedback of the evolution of the optical properties of the material on the pump pulse. We introduce an important new quantity, namely, the duration of absorption of the laser by the created plasma, corresponding to the actual timespan of laser absorption by inverse Bremsstrahlung. Our results indicate an increasing contribution of plasma absorption to the total material absorption upon raising the excitation fluence above the ablation threshold. The role of transient optical properties during the energy deposition stage is characterized and our results emphasize the necessity to take it into account for better understanding and control of femtosecond laser-dielectrics interaction.

Lebugle, M., E-mail: lebugle@lp3.univ-mrs.fr; Sanner, N.; Varkentina, N.; Sentis, M.; Utéza, O. [Aix Marseille Université, CNRS, LP3 UMR 7341, 13288 Marseille (France)

2014-08-14T23:59:59.000Z

79

Strontium isotope evidence of Neanderthal mobility at the site of Lakonis, Greece using laser-ablation PIMMS  

E-Print Network [OSTI]

Strontium isotope evidence of Neanderthal mobility at the site of Lakonis, Greece using laser the measurement of strontium isotope ratios in tooth enamel using laser- ablation, which allows us to use much in a coastal limestone cave, yet the strontium isotope values indicate the enamel was formed while

Smith, Tanya M.

80

Optical probe investigation of laser ablated carbon plasma plume in nitrogen ambient  

SciTech Connect (OSTI)

We report the study of carbon plasma produced using 1064 nm laser in nitrogen ambient at atmospheric pressure using 2-dimensional fast imaging of ablated plume, optical emission spectroscopy, and optical probe at 532 nm for interferometry and shadowgraphy. The dominance of C{sub 2} and CN molecules over ionic species at later stages of expanding carbon plasma plume is reported. The observed ring structure in shadowgrams and change in the direction of fringe shift from positive to negative in recorded interferograms are correlated with the relative abundance of different species in the plasma plume as function of time delay with respect to ablating pulse. An agreement in observed onset time of formation of clusters/atomic species or low ionic species using different diagnostic techniques has been reported.

Singh, Ravi Pratap; Gupta, Shyam L.; Thareja, Raj K. [Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016 Uttar Pradesh (India)] [Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016 Uttar Pradesh (India)

2013-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


81

Kinetics of ion and prompt electron emission from laser-produced plasma  

SciTech Connect (OSTI)

We investigated ion emission dynamics of laser-produced plasma from several elements, comprised of metals and non-metals (C, Al, Si, Cu, Mo, Ta, W), under vacuum conditions using a Faraday cup. The estimated ion flux for various targets studied showed a decreasing tendency with increasing atomic mass. For metals, the ion flux is found to be a function of sublimation energy. A comparison of temporal ion profiles of various materials showed only high-Z elements exhibited multiple structures in the ion time of flight profile indicated by the observation of higher peak kinetic energies, which were absent for low-Z element targets. The slower ions were seen regardless of the atomic number of target material propagated with a kinetic energy of 1–5 keV, while the fast ions observed in high-Z materials possessed significantly higher energies. A systematic study of plasma properties employing fast photography, time, and space resolved optical emission spectroscopy, and electron analysis showed that there existed different mechanisms for generating ions in laser ablation plumes. The origin of high kinetic energy ions is related to prompt electron emission from high-Z targets.

Farid, N. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States) [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China); Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Ding, H. [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)] [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)

2013-07-15T23:59:59.000Z

82

Quadrupole mass spectrometry and time-of-flight analysis of ions resulting from 532 nm pulsed laser ablation of Ni, Al, and ZnO targets  

SciTech Connect (OSTI)

This work describes the design and validation of an instrument to measure the kinetic energies of ions ejected by the pulsed laser ablation (PLA) of a solid target. Mass spectra show that the PLA of Ni, Al, and ZnO targets, in vacuum, using the second harmonic of a Nd:YAG laser (532 nm, pulse duration {approx}10 ns) generates abundant X{sup n+} ions (n{<=}3 for Ni, {<=}2 for Al, {<=}3 and {<=}2 for Zn and O respectively from ZnO). Ions are selected by their mass/charge (m/z) ratio prior to the determination of their times of flight. PLA of Ni has been studied in most detail. The mean velocities of ablated Ni{sup n+} ions are shown to follow the trend v(Ni{sup 3+})>v(Ni{sup 2+})>v(Ni{sup +}). Data from Ni{sup 2+} and Ni{sup 3+} are fitted to shifted Maxwellian functions and agree well with a model which assumes both thermal and Coulombic contributions to ion velocities. The dependence of ion velocities on laser pulse energy (and fluence) is investigated, and the high energy data are shown to be consistent with an effective accelerating voltage of {approx}90 V within the plume. The distribution of velocities associated with Ni{sup 3+} indicates a population at cooler temperature than Ni{sup 2+}.

Sage, Rebecca S.; Cappel, Ute B.; Ashfold, Michael N. R.; Walker, Nicholas R. [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom)

2008-05-01T23:59:59.000Z

83

Qiyin Fang MECHANISM STUDY OF SKIN TISSUE ABLATION BY NANOSECOND LASER PULSES. (Under the direction of Dr. Xin-Hua Hu)  

E-Print Network [OSTI]

in laser tissue ablation is essential to improve clinical laser applications by reducing collateral damage by nanosecond laser pulses in a wide spectral region from near-infrared to ultraviolet for a clear understanding. Multiple laser and optical configurations have been constructed to generate 9 to 12ns laser pulses

84

Combining Laser Ablation/Liquid Phase Collection Surface Sampling and High-Performance Liquid Chromatography Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

This paper describes the coupling of ambient pressure transmission geometry laser ablation with a liquid phase sample collection method for surface sampling and ionization with subsequent mass spectral analysis. A commercially available autosampler was adapted to produce a liquid droplet at the end of the syringe injection needle while in close proximity to the surface to collect the sample plume produced by laser ablation. The sample collection was followed by either flow injection or a high performance liquid chromatography (HPLC) separation of the extracted components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the analytical utility of this coupling, thin films of a commercial ink sample containing rhodamine 6G and of mixed isobaric rhodamine B and 6G dyes on glass microscope slides were analyzed. The flow injection and HPLC/ESI-MS analysis revealed successful laser ablation, capture and, with HPLC, the separation of the two compounds. The ablated circular area was about 70 m in diameter for these experiments. The spatial sampling resolution afforded by the laser ablation, as well as the ability to use sample processing methods like HPLC between the sample collection and ionization steps, makes this combined surface sampling/ionization technique a highly versatile analytical tool.

Ovchinnikova, Olga S [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

2011-01-01T23:59:59.000Z

85

Synthesis of oxidation resistant lead nanoparticle films by modified pulsed laser ablation  

SciTech Connect (OSTI)

Thin layers of lead nanoparticles have been produced by a modified pulsed laser ablation (PLA) process in which smaller nanoparticles were swept out of the ablation chamber by a stream of flowing Ar. Large ({mu}m-sized) particles, which are usually deposited during the standard PLA process, were successfully eliminated from the deposit. The nanoparticles deposited on room temperature substrates were well distributed, and the most probable particle diameter was in the order of 30 nm. Since lead is highly reactive, the nanoparticles formed in Ar were quickly oxidized upon exposure to air. A small partial pressure of H{sub 2}S gas was subsequently added to the effluent, downstream from the ablation chamber, and this resulted in the formation of nanoparticle deposits that were surprisingly oxidation resistant. The properties of the nanoparticle films (as determined by transmission electron microscopy, scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and conductivity measurements) are reported, and the mechanism of the oxidation retardation process is discussed.

Shin, Eunsung; Murray, P. Terrence; Subramanyam, Guru; Malik, Hans K.; Schwartz, Kenneth L. [Research Institute, University of Dayton, Dayton, OH 45469-0170 (United States); Research Institute, University of Dayton, Dayton, OH 45469-0170, USA and Graduate Materials Engineering, University of Dayton, Dayton, OH 45469-0240 (United States); Department of Electrical and Computer Engineering, University of Dayton, Dayton, OH 45469-0232 (United States); Northrop Grumman Electronic Systems, Linthicum, MD 21090 (United States)

2012-07-30T23:59:59.000Z

86

Indirect-drive ablative Rayleigh-Taylor growth experiments on the Shenguang-II laser facility  

SciTech Connect (OSTI)

In this research, a series of single-mode, indirect-drive, ablative Rayleigh-Taylor (RT) instability experiments performed on the Shenguang-II laser facility [X. T. He and W. Y. Zhang, Eur. Phys. J. D 44, 227 (2007)] using planar target is reported. The simulation results from the one-dimensional hydrocode for the planar foil trajectory experiment indicate that the energy flux at the hohlraum wall is obviously less than that at the laser entrance hole. Furthermore, the non-Planckian spectra of x-ray source can strikingly affect the dynamics of the foil flight and the perturbation growth. Clear images recorded by an x-ray framing camera for the RT growth initiated by small- and large-amplitude perturbations are obtained. The observed onset of harmonic generation and transition from linear to nonlinear growth regime is well predicted by two-dimensional hydrocode simulations.

Wu, J. F.; Fan, Z. F.; Zheng, W. D.; Wang, M.; Pei, W. B.; Zhu, S. P.; Zhang, W. Y. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)] [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Miao, W. Y.; Yuan, Y. T.; Cao, Z. R.; Deng, B.; Jiang, S. E.; Liu, S. Y.; Ding, Y. K. [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)] [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Wang, L. F.; Ye, W. H., E-mail: ye-wenhua@iapcm.ac.cn; He, X. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China) [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); HEDPS, Center for Applied Physics and Technology, Peking University, Beijing 100871 (China)

2014-04-15T23:59:59.000Z

87

Investigation of effect of solenoid magnet on emittances of ion beam from laser ablation plasma  

SciTech Connect (OSTI)

A magnetic field can increase an ion current of a laser ablation plasma and is expected to control the change of the plasma ion current. However, the magnetic field can also make some fluctuations of the plasma and the effect on the beam emittance and the emission surface is not clear. To investigate the effect of a magnetic field, we extracted the ion beams under three conditions where without magnetic field, with magnetic field, and without magnetic field with higher laser energy to measure the beam distribution in phase space. Then we compared the relations between the plasma ion current density into the extraction gap and the Twiss parameters with each condition. We observed the effect of the magnetic field on the emission surface.

Ikeda, Shunsuke, E-mail: shunsuke.ikeda@riken.jp; Sekine, Megumi [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan) [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan); Riken, Wako, Saitama (Japan); Romanelli, Mark [Cornell University, Ithaca, New York 14850 (United States)] [Cornell University, Ithaca, New York 14850 (United States); Cinquegrani, David [University of Michigan, Ann Arbor, Michigan 48109 (United States)] [University of Michigan, Ann Arbor, Michigan 48109 (United States); Kumaki, Masafumi [Waseda University, Shinjuku, Tokyo (Japan)] [Waseda University, Shinjuku, Tokyo (Japan); Fuwa, Yasuhiro [Kyoto University, Uji, Kyoto (Japan)] [Kyoto University, Uji, Kyoto (Japan); Kanesue, Takeshi; Okamura, Masahiro [Brookhaven National Laboratory, Upton, New York 11973 (United States)] [Brookhaven National Laboratory, Upton, New York 11973 (United States); Horioka, Kazuhiko [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan)] [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan)

2014-02-15T23:59:59.000Z

88

The role of asymmetric excitation in self-organized nanostructure formation upon femtosecond laser ablation  

SciTech Connect (OSTI)

Surface pattering upon multi-pulse femtosecond laser ablation is modeled by a non-linear-dynamic erosion/smoothing model, similar to structure formation during ion sputtering. The model is adopted to account for the influence of laser polarization on nanostructure features. Based on a nonlinear equation of the Kuramoto-Siavshinsky type, it is shown that the directional anisotropy in the pattern formation may result from a spatial anisotropy of the initial excitation/energy-coupling process, such as resonant coupling to surface plasmons/polaritons, or electron diffusion properties. Also, anisotropy of elasto-dynamic surface and diffusion properties may be involved. A comparison of numeric simulations based on the model with corresponding experi-mental results gives a very good agreement.

Reif, Juergen; Varlamova, Olga; Varlamov, Sergej; Bestehorn, Michael [Brandenburgische Technische Universitaet (BTU) Cottbus Platz der Deutschen Einheit 1, 03046 Cottbus (Germany); Brandenburgische Technische Universitaet (BTU) Cottbus Platz der Deutschen Einheit 1, 03046 Cottbus (Germany)

2012-07-30T23:59:59.000Z

89

Safeguards Verification Measurements using Laser Ablation, Absorbance Ratio Spectrometry in Gaseous Centrifuge Enrichment Plants  

SciTech Connect (OSTI)

Laser Ablation Absorbance Ratio Spectrometry (LAARS) is a new verification measurement technology under development at the US Department of Energy’s (DOE) Pacific Northwest National Laboratory (PNNL). LAARS uses three lasers to ablate and then measure the relative isotopic abundance of uranium compounds. An ablation laser is tightly focused on uranium-bearing solids producing a small plume containing uranium atoms. Two collinear wavelength-tuned spectrometry lasers transit through the plume and the absorbance of U-235 and U-238 isotopes are measured to determine U-235 enrichment. The measurement has high relative precision and detection limits approaching the femtogram range for uranium. It is independent of chemical form and degree of dilution with nuisance dust and other materials. High speed sample scanning and pinpoint characterization allow measurements on millions of particles/hour to detect and analyze the enrichment of trace uranium in samples. The spectrometer is assembled using commercially available components at comparatively low cost, and features a compact and low power design. Future designs can be engineered for reliable, autonomous deployment within an industrial plant environment. Two specific applications of the spectrometer are under development: 1) automated unattended aerosol sampling and analysis and 2) on-site small sample destructive assay measurement. The two applications propose game-changing technological advances in gaseous centrifuge enrichment plant (GCEP) safeguards verification. The aerosol measurement instrument, LAARS-environmental sampling (ES), collects aerosol particles from the plant environment in a purpose-built rotating drum impactor and then uses LAARS-ES to quickly scan the surface of the impactor to measure the enrichments of the captured particles. The current approach to plant misuse detection involves swipe sampling and offsite analysis. Though this approach is very robust it generally requires several months to obtain results from a given sample collection. The destructive assay instrument, LAARS-destructive assay (DA), uses a simple purpose-built fixture with a sampling planchet to collect adsorbed UF6 gas from a cylinder valve or from a process line tap or pigtail. A portable LAARS-DA instrument scans the microgram quantity of uranium collected on the planchet and the assay of the uranium is measured to ~0.15% relative precision. Currently, destructive assay samples for bias defect measurements are collected in small sample cylinders for offsite mass spectrometry measurement.

Anheier, Norman C.; Cannon, Bret D.; Qiao, Hong (Amy) [Amy; Phillips, Jon R.

2012-07-01T23:59:59.000Z

90

Structural and magnetic properties of NiZn and Zn ferrite thin films obtained by laser ablation deposition  

E-Print Network [OSTI]

Structural and magnetic properties of NiZn and Zn ferrite thin films obtained by laser ablation ferrite structures. Our investigations were performed on NiZn and Zn ferrite films deposited on silicon of the blocking temperature in both NiZn and Zn ferrite systems. © 2005 American Institute of Physics. DOI: 10

McHenry, Michael E.

91

SF2I.7.pdf CLEO:2014 2014 OSA Emission and expansion features of ns and fs laser ablation  

E-Print Network [OSTI]

of an ambient leading to further excitation of plume species as well as enhancing excited molecular species and hydrodynamic expansion dynamics of ns and fs laser ablated metal plasmas in the presence of an ambient were studied. The structure and dynamics of both ns and fs plumes obtained from optical diagnostic

Harilal, S. S.

92

Addition and recombination reactions of unsaturated radicals using a novel laser kinetics spectrometer  

E-Print Network [OSTI]

This thesis describes the construction of a novel, low-noise laser kinetics spectrometer. A quasi-CW (picosecond pulse), tunable Ti:Sapphire laser is used to detect various transient species in laser flash photolysis ...

Ismail, Huzeifa

2008-01-01T23:59:59.000Z

93

Absorption of a single 500 fs laser pulse at the surface of fused silica: Energy balance and ablation efficiency  

SciTech Connect (OSTI)

Ablation of fused silica by a single femtosecond laser pulse of 500 fs pulse duration is investigated from the perspective of efficiency of incident photons to remove matter. We measure the reflected and transmitted fractions of the incident pulse energy as a function of fluence, allowing us to recover the evolution of absorption at the material surface. At the ablation threshold fluence, 25% of incident energy is absorbed. At high fluences, this ratio saturates around 70% due to the appearance of a self-triggered plasma mirror (or shielding) effect. By using the energy balance retrieved experimentally and measurements of the ablated volume, we show that the amount of absorbed energy is far above the bonding energy of fused silica at rest and also above the energy barrier to ablate the material under non-equilibrium thermodynamic conditions. Our results emphasize the crucial role of transient plasma properties during the laser pulse and suggest that the major part of the absorbed energy has been used to heat the plasma formed at the surface of the material. A fluence range yielding an efficient and high quality ablation is also defined, which makes the results relevant for femtosecond micromachining processes.

Varkentina, N.; Sanner, N.; Lebugle, M.; Sentis, M.; Utéza, O. [Aix-Marseille Université, CNRS, LP3 UMR 7341, 13288 Marseille (France)] [Aix-Marseille Université, CNRS, LP3 UMR 7341, 13288 Marseille (France)

2013-11-07T23:59:59.000Z

94

Photoemission Studies of Metallic Photocathodes Prepared by Pulsed Laser Ablation Deposition Technique  

SciTech Connect (OSTI)

We present the results of our investigation on metallic films as suitable photocathodes for the production of intense electron beams in RF photoinjector guns. Pulsed laser ablation deposition technique was used for growing Mg and Y thin films onto Si and Cu substrates in high vacuum and at room temperature.Different diagnostic methods were used to characterize the thin films deposited on Si with the aim to optimize the deposition process. Photoelectron performances were investigated on samples deposited on Cu substrate in an ultra high vacuum photodiode chamber at 10{sup -7} Pa. Relatively high quantum efficiencies have been obtained for the deposited films, comparable to those of corresponding bulks. Samples could stay for several months in humid open air before being tested in a photodiode cell. The deposition process and the role of the photocathode surface contamination and its influence on the photoelectron performances are presented and discussed.

Fasano, V.; Lorusso, A.; Perrone, A. [National Institute of Nuclear Physics and Physics Department, University of Salento, Via Arnesano, 73100-Lecce (Italy); De Rosa, H. [Laboratorio de Metalografia, Dpto. Ingenieria Mecanica y Naval, Facultad de Ingenieria, Universidad de Buenos Aires (Argentina); Cultrera, L. [National Institute of Nuclear Physics, National Laboratories, Frascati (Italy)

2010-11-10T23:59:59.000Z

95

Imaging the ultrafast Kerr effect, free carrier generation, relaxation and ablation dynamics of Lithium Niobate irradiated with femtosecond laser pulses  

SciTech Connect (OSTI)

The interaction of high-power single 130 femtosecond (fs) laser pulses with the surface of Lithium Niobate is experimentally investigated in this work. The use of fs-resolution time-resolved microscopy allows us to separately observe the instantaneous optical Kerr effect induced by the pulse and the generation of a free electron plasma. The maximum electron density is reached 550?fs after the peak of the Kerr effect, confirming the presence of a delayed carrier generation mechanism. We have also observed the appearance of transient Newton rings during the ablation process, related to optical interference of the probe beam reflected at the front and back surface of the ablating layer. Finally, we have analyzed the dynamics of the photorefractive effect on a much longer time scale by measuring the evolution of the transmittance of the irradiated area for different fluences below the ablation threshold.

Garcia-Lechuga, Mario, E-mail: mario@io.cfmac.csic.es; Siegel, Jan, E-mail: j.siegel@io.cfmac.csic.es; Hernandez-Rueda, Javier; Solis, Javier [Laser Processing Group, Instituto de Optica, CSIC, Serrano 121, 28006 Madrid (Spain)

2014-09-21T23:59:59.000Z

96

Understanding plume splitting of laser ablated plasma: A view from ion distribution dynamics  

SciTech Connect (OSTI)

Plume splitting in low-pressure ambient air was understood in view of ion distribution dynamics from the laser ablated Al plasma (1064 nm 0.57 J/mm{sup 2}) by combining fast photography and spatially resolved spectroscopy. In the beginning, the spectral lines were mainly from the Al III ion. Then, the Bragg peak in stopping power of the ambient gas to Al III could be the dominant reason for the enhanced emission from the fast moving part, and the recombination of Al III to Al I-II ions near the target surface was response to the radiations from the slow moving/stationary part. As the ambient gas pressure increased, stopping distances of the Al III decreased, and radiation from the air ions became pronounced. The laser shadowgraph image at 1100 Pa indicated that the shock wave front located between the fast moving and slow moving parts. Electron densities of the fast moving plasma, which peaked at the plasma front, were on the order of 10{sup 16} cm{sup ?3}, and the electron temperatures were 2–3 eV.

Wu, Jian; Li, Xingwen; Wei, Wenfu; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)

2013-11-15T23:59:59.000Z

97

Growth of highly doped p-type ZnTe films by pulsed laser ablation in molecular nitrogen  

SciTech Connect (OSTI)

Highly p-doped ZnTe films have been grown on semi-insulating GaAs (001) substrates by pulsed-laser ablation (PLA) of a stoichiometric ZnTe target in a high-purity N{sub 2} ambient without the use of any assisting (DC or AC) plasma source. Free hole concentrations in the mid-10{sup 19} cm{sup {minus}3} to > 10{sup 20} cm{sup {minus}3} range were obtained for a range of nitrogen pressures The maximum hole concentration equals the highest hole doping reported to date for any wide band gap II-VI compound. The highest hole mobilities were attained for nitrogen pressures of 50--100 mTorr ({approximately}6.5-13 Pa). Unlike recent experiments in which atomic nitrogen beams, extracted from RF and DC plasma sources, were used to produce p-type doping during molecular beam epitaxy deposition, spectroscopic measurements carried out during PLA of ZnTe in N{sub 2} do not reveal the presence of atomic nitrogen. This suggests that the high hole concentrations in laser ablated ZnTe are produced by a new and different mechanism, possibly energetic beam-induced reactions with excited molecular nitrogen adsorbed on the growing film surface, or transient formation of Zn-N complexes in the energetic ablation plume. This appears to be the first time that any wide band gap (Eg > 2 eV) II-VI compound (or other) semiconductor has been impurity-doped from the gas phase by laser ablation. In combination with the recent discovery that epitaxial ZnSe{sub l-x}S{sub x} films and heterostructures with continuously variable composition can be grown by ablation from a single target of fixed composition, these results appear to open the way to explore PLA growth and doping of compound semiconductors as a possible alternative to molecular beam epitaxy.

Lowndes, D.H.; Rouleau, C.M.; Budai, J.D.; Poker, D.B.; Geohegan, D.B.; Zhu, Shen [Oak Ridge National Lab., TN (United States); McCamy, J.W. [Harvard Univ., Cambridge, MA (United States). Div. of Applied Science; Puretzky, A. [Institute of Spectroscopy, Troitsk (Russian Federation)

1995-04-01T23:59:59.000Z

98

Resonant high-order harmonic generation from plasma ablation: Laser intensity dependence of the harmonic intensity and phase  

SciTech Connect (OSTI)

Experimentally observed strong enhancement of a single high-order harmonic in harmonic generation from low-ionized laser plasma ablation is explained as resonant harmonic generation. The resonant harmonic intensity increases regularly with the increase of the laser intensity, while the phase of the resonant harmonic is almost independent of the laser intensity. This is in sharp contrast with the usual plateau and cutoff harmonics, the intensity of which exhibits wild oscillations while its phase changes rapidly with the laser intensity. The temporal profile of a group of harmonics, which includes the resonant harmonic, has the form of a broad peak in each laser-field half cycle. These characteristics of resonant harmonics can have an important application in attoscience. We illustrate our results using examples of Sn and Sb plasmas.

Milosevic, D. B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Str. 2a, D-12489 Berlin (Germany)

2010-02-15T23:59:59.000Z

99

ablation mass spectrometry: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and laser ablation electrospray ionization mass Chemistry Websites Summary: -mass spectrometry (DESI-MS) and laser ablation electrospray ionization-MS (LAESI-MS) were used to...

100

Campaign-style titanite UPb dating by laser-ablation ICP: Implications for crustal flow, phase transformations and titanite closure  

E-Print Network [OSTI]

Campaign-style titanite U­Pb dating by laser-ablation ICP: Implications for crustal flow, phase transformations and titanite closure K.J. Spencer a , B.R. Hacker a, , A.R.C. Kylander-Clark a , T.B. Andersen b Editor: K. Mezger Keywords: Titanite Ultrahigh-pressure U­Pb Norway U­Pb dates of titanite from >150

Hacker, Bradley R.

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

A Langmuir Probe Diagnostic for Use in Inhomogeneous, Time-Varying Plasmas Produced by High-Energy Laser Ablation  

SciTech Connect (OSTI)

Langmuir probes (LP) are used extensively to characterize plasma environments produced by radio frequency, pulsed plasma thrusters, and laser ablation. We discuss here the development of a LP diagnostic to examine high-density, high-temperature inhomogeneous plasmas such as those that can be created at the University of Rochester's Laboratory for Laser Energetics OMEGA facility. We have configured our diagnostic to examine the velocity of the plasma expanding from the target. We observe velocities of approximately 16-17 cm/{micro}s, with individual LP currents displaying complex structures, perhaps due to the multiple atomic species and ionization states that exist.

Patterson, J R; Emig, J A; Fournier, K B; Jenkins, P P; Trautz, K M; Seiler, S W; Davis, J F

2012-05-01T23:59:59.000Z

102

Structural and optical properties of {beta}-FeSi{sub 2}/Si(100) prepared by laser ablation method  

SciTech Connect (OSTI)

{beta}-FeSi{sub 2} is a promising material for the application of various electronic, optoelectronic and energy devices. The authors present here the semiconducting properties of {beta}-FeSi{sub 2} films on Si(100) substrate prepared by laser ablation method. Samples were grown using poly-crystalline bulk {beta}-FeSi{sub 2} prepared by horizontal gradient freeze method. For the monitoring of growth, in-situ observation of ablation plume was made through fluorescence spectroscopy. Reflection of high-energy electron beam diffraction (RHEED) was also made in-situ to see the surface morphology. Characterization of the films by X-ray diffraction presented purely {beta}(220) orientation. Raman scattering measurements at room temperature also indicated that the grown films are semiconducting {beta}-FeSi{sub 2}. Optical absorption spectra at room temperature showed absorption coefficient higher than 10{sup 5} cm{sup {minus}1} above the band-gap ({approximately}1.2 eV). It was revealed that high quality semiconducting {beta}-FeSi{sub 2} films can be fabricated by laser ablation method without post-annealing.

Kakemoto, H.; Makita, Y.; Obara, A.; Tsai, Y.; Sakuragi, S.; Ando, S.; Tsukamoto, T.

1997-07-01T23:59:59.000Z

103

Long-Time Feedback in the Formation of Self-Organized Nanostructures upon Multipulse Femtosecond Laser Ablation  

SciTech Connect (OSTI)

The self-organization feedback in nanostructures (ripples) formation upon femtosecond laser ablation is investigated in detail, with particular emphasis on its dynamics. We study the influence of time separation between successive pulses on both the size and complexity of the nanostructures and on the size of the modified surface area. By varying the pulse separation between 1 ms and 1 s (rep. rate between 1 kHz and 1 Hz), we find that both modified area as well as pattern feature size and complexity decrease with increasing pulse-to-pulse delay, indicating that the coupling efficiency between laser and target increases with increasing repetition rate. Structure formation resulting from surface instability, induced by the laser impact, suggests that the laser-induced instability results in a transient increase of absorption probability, slowly decaying in time. The stronger this transient absorption, the better is the coupling for the succeeding pulse, thus resulting in a positive feedback. Experimental results indicate that the lifetime of the feedback can last up to one second and longer.In addition, a persisting modulated spatial modification of crystalline properties is observed well beyond the ablation spot, though no apparent influence on surface morphology is seen. Mapping the band-to-band photoluminescence from silicon indicates a dramatic increase of non-radiative recombination compared to unaffected material.

Reif, Juergen; Varlamova, Olga [Brandenburgische Technische Universitaet (BTU) Cottbus Universitaetsstr. 1, 03046 Cottbus (Germany); Cottbus JointLab, Erich-Weinert-Str. 1, 03046 Cottbus (Germany); Bounhalli, Mourad [Brandenburgische Technische Universitaet (BTU) Cottbus Universitaetsstr. 1, 03046 Cottbus (Germany); Laboratoire Hubert Curien, Universite Jean Monnet, Saint-Etienne (France); Arguirov, Tzanimir [Cottbus JointLab, Erich-Weinert-Str. 1, 03046 Cottbus (Germany); IHP-Leibniz-Institut fuer innovative Mikroelektronik, Frankfurt (Germany)

2010-10-08T23:59:59.000Z

104

Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry  

SciTech Connect (OSTI)

Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

Perdian, David C.

2009-08-19T23:59:59.000Z

105

Direct periodic patterning of GaN-based light-emitting diodes by three-beam interference laser ablation  

SciTech Connect (OSTI)

We report on the direct patterning of two-dimensional periodic structures in GaN-based light-emitting diodes (LEDs) through laser interference ablation for the fast and reliable fabrication of periodic micro- and nano-structures aimed at enhancing light output. Holes arranged in a two-dimensional hexagonal lattice array having an opening size of 500?nm, depth of 50?nm, and a periodicity of 1??m were directly formed by three-beam laser interference without photolithography or electron-beam lithography processes. The laser-patterned LEDs exhibit an enhancement in light output power of 20% compared to conventional LEDs having a flat top surface without degradation of electrical and optical properties of the top p-GaN layer and the active region, respectively.

Kim, Jeomoh; Ji, Mi-Hee; Detchprohm, Theeradetch [Center for Compound Semiconductors and School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States); Yuan, Dajun; Guo, Rui [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); Liu, Jianping [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215125 (China); Asadirad, Mojtaba [Materials Engineering Program, University of Houston, Houston, Texas 77204-4005 (United States); Kwon, Min-Ki [Department of Photonic Engineering, Chosun University, Seosuk-dong, Gwangju 501-759 (Korea, Republic of); Dupuis, Russell D. [Center for Compound Semiconductors and School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Das, Suman [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245 (United States); Ryou, Jae-Hyun, E-mail: jryou@uh.edu [Materials Engineering Program, University of Houston, Houston, Texas 77204-4005 (United States); Department of Mechanical Engineering and Texas Center for Superconductivity at the University of Houston (TcSUH), University of Houston, Houston, Texas 77204-4006 (United States)

2014-04-07T23:59:59.000Z

106

Developing the model of laser ablation by considering the interplay between emission and expansion of aluminum plasma  

SciTech Connect (OSTI)

In the present study, the ablation behavior of aluminum target and its plasma radiation in noble ambient gases by a laser pulse with wavelength of 266 nm and pulse duration of 10 ns are numerically studied. A thermal model of laser ablation considering heat conduction, Euler equations, Saha-Eggert equations, Knudsen layer, mass and energy balance relations and optical shielding effects are used for calculation of plasma parameters. Effects of excitation energy on plasma expansion and its emissivity are investigated. Time and spatial-resolved plasma emission including bremsstrahlung, recombination and spectral emission at early delay times after laser irradiation is obtained. Effects of two ambient gases (He and Ar) as well as different gas pressures of 100, 300, 500, and 760 Torr on plasma expansion and its spectrum are studied. Results illustrate that at initial delay times, especially at high noble gas pressures, ionic lines have the maximum intensities, while at later times neutral lines dominate. When the pressure of ambient gas increases, a confinement of the plasma plume is predicted and the intensity of neutral lines decreases. Continuous emission increases with wavelength in both ambient gases. Spatially resolved analysis shows that an intense continuous emission is predicted next to the sample surface decreasing with distance from the latter.

Rezaei, F.; Tavassoli, S. H. [Laser and Plasma Research Institute, ShahidBeheshti University, 19396 4716, G. C., Evin, Tehran (Iran, Islamic Republic of)

2013-01-15T23:59:59.000Z

107

Pulsed laser kinetic studies of liquids under high pressure  

SciTech Connect (OSTI)

A laser flash photolysis kinetic study of 2,2{prime}-bipyridine bidentate chelating ligands with one claw in the first coordination sphere of a molybdenum carbonyl complex has been completed at pressures up to 150 MPa. The reaction mechanism for thermal ring closure is found from activation volumes to change from associative interchange to dissociative interchange as substituents on the 2,2{prime}-bipyridine ligands become bulkier. In a similar study of more rigid, substituted phenanthroline bidentate ligands it was found that substituent bulkiness had little effect on the thermal ring closure mechanism. Stability constants for lithium ion complexes with crown ethers in a room temperature molten salt, fluorescence quantum yields for cresyl violet and several other dyes in solution, and the oxidation of alcohols by OsO{sub 4} have also been investigated.

Eyring, E.M.

1992-09-22T23:59:59.000Z

108

Pulsed laser kinetic studies of liquids under high pressure  

SciTech Connect (OSTI)

A high pressure apparatus constructed for measuring the rates of reactions in liquids under pressures ranging from 1 atm to 2000 atm has been used to measure the complexation kinetics of molybdenum hexacarbonyl reacting with 2,2-bipyridine, 4,4{prime}-dimethyl-2-2{prime}-bipyridine and 4,4{prime}-diphenyl-2-2{prime} bipyridine in toluene. Pentacarbonyl reaction intermediates are created by a 10 nsec flash of frequency tripled Nd:YAG laser light. Measured activation volumes for chelate ligand ring closure indicate a change in mechanism from associative interchange to dissociative interchange as steric hindrance increases. A similar high pressure kinetics study of molybdenum carbonyl complexation by several substituted phenanthrolines is now well advanced that indicates that with the more rigid phenanthroline ligands steric effects from bulky substituents have less effect on the ring closure mechanism than in the case of the bipyridine ligands. An experimental concentration dependence of the fluorescence quantum yield of cresyl violet has been harmonized with previously published contradictory reports. Fluorescence of cresyl violet in various solvents and in micellar systems has also been systematically explored.

Eyring, E.M.

1991-11-25T23:59:59.000Z

109

Laser Ablation of Metals Johannes Roth, Carolina Trichet, Hans-Rainer-Trebin, and Steffen Sonntag  

E-Print Network [OSTI]

radiation. It is a technology which gains increasingly greater importance for drilling, eroding, welding especially, a large number of new processing methods were developed. A deeper understanding of the ablation natural. IMD has been adapted to new computer architectures and optimized continuously. Thus it is very

Roth, Johannes

110

Emission features of femtosecond laser ablated carbon plasma in ambient K. F. Al-Shboul, S. S. Harilal, and A. Hassanein  

E-Print Network [OSTI]

Emission features of femtosecond laser ablated carbon plasma in ambient helium K. F. Al-Shboul, S carbon species in the plume were obtained using time of flight emission spectroscopy. These contours 2013; published online 30 April 2013) We investigated the optical emission features of plasmas produced

Harilal, S. S.

111

E-Print Network 3.0 - ablation plasma induced Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

search results for: ablation plasma induced Page: << < 1 2 3 4 5 > >> 1 RESONANCE LASER ABLATION WITH AN OPTICAL PARAMETRIC OSCILLATOR LASER AND DETECTION BY A Summary: were...

112

In situ diagnostic of the size distribution of nanoparticles generated by ultrashort pulsed laser ablation in vacuum  

SciTech Connect (OSTI)

We aim to characterize the size distribution of nanoparticles located in the ablation plume produced by femtosecond laser interaction. The proposed method relies on the use of white-light extinction spectroscopy setup assisted by ultrafast intensified temporal gating. This method allows measurement of optical absorbance of a nickel nanoparticles cloud. Simulation of the extinction section of nickel nanoparticles size distributions has been developed in order to compare the measured optical absorbance to the optical extinction by theoretical and experimental nanoparticles size distributions (measured by scanning electron microscopy). A good agreement has been found between the in situ measured optical absorbance and the optical extinction cross section calculated from ex situ nanoparticles size distribution measurements.

Bourquard, Florent; Loir, Anne-Sophie; Donnet, Christophe; Garrelie, Florence, E-mail: florence.garrelie@univ-st-etienne.fr [Université de Lyon, CNRS UMR 5516, Laboratoire Hubert Curien, Université Jean Monnet, Saint-Étienne (France)] [Université de Lyon, CNRS UMR 5516, Laboratoire Hubert Curien, Université Jean Monnet, Saint-Étienne (France)

2014-03-10T23:59:59.000Z

113

Laser Ablation Sampling of Materials Directly into the Formed Liquid Microjunction of a Continuous Flow Surface Sampling Probe/Electrospray Ionization Emitter for Mass Spectral Analysis and Imaging  

SciTech Connect (OSTI)

Transmission geometry laser ablation directly into a formed liquid microjunction of a continuous flow liquid microjunction surface sampling probe/electrospray ionization emitter was utilized for molecular and elemental detection and mass spectrometry imaging. The ability to efficiently capture and ionize ablated material was demonstrated by the detection of various small soluble n-mers of polyaniline and silver ion solvent clusters formed from laser ablation of electropolymerized polyaniline and silver thin films, respectively. In addition, analysis of surfaces that contain soluble components was accomplished by coating or laminating the sample with an insoluble film to enable liquid junction formation without directly extracting material from the surface. The ability to perform mass spectrometry imaging at a spatial resolution of about 50 m was illustrated by using laminated inked patterns on a microscope slide. In general, these data demonstrate at least an order of magnitude signal enhancement compared to the non-contact, laser ablation droplet capture-based surface sampling/ionization approaches that have been previously presented.

Ovchinnikova, Olga S [ORNL] [ORNL; Lorenz, Matthias [ORNL] [ORNL; Kertesz, Vilmos [ORNL] [ORNL; Van Berkel, Gary J [ORNL] [ORNL

2013-01-01T23:59:59.000Z

114

High throughput solar cell ablation system  

DOE Patents [OSTI]

A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

2012-09-11T23:59:59.000Z

115

High throughput solar cell ablation system  

DOE Patents [OSTI]

A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

2014-10-14T23:59:59.000Z

116

Optical far- and near-field femtosecond laser ablation of Si for nanoscale chemical analysis  

SciTech Connect (OSTI)

Extending spatial resolution in laser-based chemical analysis to the nanoscale becomes increasingly important as nanoscience and nanotechnology develop. Implementation of femtosecond laser pulses arises as a basic strategy for increasing resolution since it is associated with spatially localized material damage. In this work we study femtosecond laser far- and near-field processing of silicon (Si) at two distinct wavelengths (400 and 800 nm), for nanoscale chemical analysis. By tightly focusing femtosecond laser beams in the far-field we were able to produce sub-micrometer craters. In order to further reduce the crater size, similar experiments were performed in the near-field through sub-wavelength apertures, resulting to the formation of sub-30 nm craters. Laser Induced Breakdown Spectroscopy (LIBS) was used for chemical analysis with a goal to identify the minimum crater size from which spectral emission could be measured. Emission from sub-micrometer craters (full-with-at-half-maximum) was possible, which are among the smallest ever reported for femtosecond LIBS.

Zormpa, Vasileia; Mao, Xianglei; Russo, Richard E.

2010-02-02T23:59:59.000Z

117

Photonic crystal formation on optical nanofibers using femtosecond laser ablation technique  

E-Print Network [OSTI]

We demonstrate that thousands of periodic nano-craters are fabricated on a subwavelength-diameter tapered optical fiber, an optical nanofiber, by irradiating with just a single femtosecond laser pulse. A key aspect of the fabrication is that the nanofiber itself acts as a cylindrical lens and focuses the femtosecond laser beam on its shadow surface. We also demonstrate that such periodic structures on the nanofiber, act as a 1-D photonic crystal (PhC). Such PhC structures on the nanofiber will strongly enhance the field confinement in such a tapered fiber-based system and may open new avenues in nanophotonics and quantum information technology.

Nayak, K P

2012-01-01T23:59:59.000Z

118

Photonic crystal formation on optical nanofibers using femtosecond laser ablation technique  

E-Print Network [OSTI]

We demonstrate that thousands of periodic nano-craters are fabricated on a subwavelength-diameter tapered optical fiber, an optical nanofiber, by irradiating with just a single femtosecond laser pulse. A key aspect of the fabrication is that the nanofiber itself acts as a cylindrical lens and focuses the femtosecond laser beam on its shadow surface. We also demonstrate that such periodic structures on the nanofiber, act as a 1-D photonic crystal (PhC). Such PhC structures on the nanofiber will strongly enhance the field confinement in such a tapered fiber-based system and may open new avenues in nanophotonics and quantum information technology.

K. P. Nayak; K. Hakuta

2012-10-29T23:59:59.000Z

119

Characterization of hydrocarbon and mixed layers in TEXTOR by laser induced ablation spectroscopy  

E-Print Network [OSTI]

: 134.95.83.67 The article was downloaded on 10/03/2012 at 13:13 Please note that terms and conditions apply. View the table of contents for this issue, or go to the journal homepage for more Home Search the plasma discharge by intense laser radiation. The light emitted by particles entering the edge

Giesen, Thomas

120

Catalytic nanoparticles for carbon nanotube growth synthesized by through thin film femtosecond laser ablation  

E-Print Network [OSTI]

within the distribution, suggesting that nanoparticle formation by gas phase condensation was not at play techniques were largely the result of condensation of a laser-induced plume in a background gas. Femtosecond of divergence of ~2.5º) which were cleanly deposited onto different supports for analysis. TEM showed

Geohegan, David B.

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle Cormier-Michel,1,2  

E-Print Network [OSTI]

Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle of laser wakefield accelerators using particle-in-cell codes are investigated. A dark current free laser wakefield accelerator stage, in which no trapping of background plasma electrons into the plasma wave should

Geddes, Cameron Guy Robinson

122

Investigation of gain kinetics in a CO gas dynamic laser  

SciTech Connect (OSTI)

A detailed experimental investigation of small-signal gain in a CO gasdynamic laser, produced in a shock tunnel is presented. Gains of the P/sub 7/(3) transition were measured at a distance 44 cm downstream from the nozzle throat for various CO--Ar and CO--N/sub 2/--Ar mixtures at stagnation temperatures of 1800/sup 0/--3800 /sup 0/K and stagnation pressures of 18--40 atm. Optimum gas temperatures and compositions were observed. Laser oscillations were observed simultaneously in two cavities located at 44 and 56 cm downstream from the nozzle throat. The experimental data on gain have been compared with a numerical model. A quantitatively good argeement between calculations and experiments was found which permits the utilization of the mathematical model for a better understanding of the processes involved in the laser operation. Small signal gains and multi-line laser power outputs were calculated along the nozzle for various initial conditions. Calculations indicate that maximum gain and maximum power occur for P/sub 3/(4)-P/sub 5/(4) lines at a stagnation temperature of about 3000 /sup 0/K and a gas composition of CO:Ar = 20:80.

Stricker, J.; Tilleman, M.

1982-06-01T23:59:59.000Z

123

E-Print Network 3.0 - ablated plasma width Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ablated plasma width Page: << < 1 2 3 4 5 > >> 1 ORIGINAL ARTICLE Ultrashort pulsed laser ablation and stripping Summary: Springer-Verlag London Ltd 2009 Abstract...

124

Pulsed laser kinetic studies of liquids under high pressure  

SciTech Connect (OSTI)

Experiments have been developed for measuring the rates of chemical reactions liquids and in supercritical Co[sub 2]. A pulsed (Q-switch) Nd:YAG laser at 355 nm was the pump beam for laser flash photolysis studies of molybdenum and tungsten hexacarbonyls undergoing ligand displacement reactions by bidentate chelating agents such as 2,2[prime]-bipyridine in toluene. Experiments were carried out at 0.1 to 150 MPa. In the case of molybdenum complexes, the reaction mechanism for thermal ring closure is found from activation volumes to change from associative interchange to dissociative interchange as substituents on the 2,2[prime]-bipyridine ligands become bulkier. In a similar study of more rigid, substituted phenanthroline bidentate ligands it was found that substituent bulkiness had little effect on the thermal ring closure mechanism. Similar high pressure flash photolysis experiments with tungsten hexacarbonyl have also been completed. The concentration dependence of the fluorescence and nonradiative decay quantum yields for cresyl violet in several solvent have been reported as well as stability constants for the complexation of lithium ion by four different crown ethers dissolved in a room temperature molten salt.

Eyring, E.M.

1993-06-21T23:59:59.000Z

125

Current developments in laser ablation-inductively coupled plasma-mass spectrometry for use in geology, forensics, and nuclear nonproliferation research  

SciTech Connect (OSTI)

This dissertation focused on new applications of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The diverse fields that were investigated show the versatility of the technique. In Chapter 2, LA-ICP-MS was used to investigate the rare earth element (REE) profiles of garnets from the Broken Hill Deposit in New South Wales, Australia. The normalized REE profiles helped to shed new light on the formation of deposits of sulfide ores. This information may be helpful in identifying the location of sulfide ore deposits in other locations. New sources of metals such as Pg, Zn, and Ag, produced from these ores, are needed to sustain our current technological society. The application of LA-ICP-MS presented in Chapter 3 is the forensics analysis of automotive putty and caulking. The elemental analysis of these materials was combined with the use of Principal Components Analysis (PCA). The PCA comparison was able to differentiate the automotive putty samples by manufacturer and lot number. The analysis of caulk was able to show a differentiation based on manufacturer, but no clear differentiation was shown by lot number. This differentiation may allow matching of evidence in the future. This will require many more analyses and the construction of a database made up of many different samples. The 4th chapter was a study of the capabilities of LA-ICP-MS for fast and precise analysis of particle ensembles for nuclear nonproliferation applications. Laser ablation has the ability to spatially resolve particle ensembles which may contain uranium or other actinides from other particles present in a sample. This is of importance in samples obtained from air on filter media. The particle ensembles of interest may be mixed in amongst dust and other particulates. A problem arises when ablating these particle ensembles directly from the filter media. Dust particles other than ones of interest may be accidentally entrained in the aerosol of the ablated particle ensemble. This would cause the analysis to be skewed. The use of a gelatin substrate allows the ablation a particle ensemble without disturbing other particles or the gelatin surface. A method to trap and ablate particles on filter paper using collodion was also investigated. The laser was used to dig through the collodion layer and into the particle ensemble. Both of these methods fix particles to allow spatial resolution of the particle ensembles. The use of vanillic acid as a possible enhancement to ablation was also studied. A vanillic acid coating of the particles fixed on top of the gelatin substrate was not found to have any positive effect on either signal intensity or precision. The mixing of vanillic acid in the collodion solution used to coat the filter paper increased ablation signal intensity by a factor of 4 to 5. There was little effect on precision, though. The collodion on filter paper method and the gelatin method of resolving particles have shown themselves to be possible tools in fighting proliferation of nuclear weapons and material. Future applications of LA-ICP-MS are only limited by the imagination of the investigator. Any material that can be ablated and aerosolized is a potential material for analysis by LA-ICP-MS. Improvements in aerosol transport, ablation chamber design, and laser focusing can make possible the ablation and analysis of very small amounts of material. This may perhaps lead to more possible uses in forensics. A similar method to the one used in Chapter 3 could perhaps be used to match drug residue to the place of origin. Perhaps a link could be made based on the elements leached from the soil by plants used to make drugs. This may have a specific pattern based on where the plant was grown. Synthetic drugs are produced in clandestine laboratories that are often times very dirty. The dust, debris, and unique materials in the lab environment could create enough variance to perhaps match drugs produced there to samples obtained off the street. Even if the match was not strong enough to be evidence, the knowledge that many sa

Messerly, Joshua D.

2008-08-26T23:59:59.000Z

126

Kinetic simulation studies of laser-triggering in the Z gas switch  

SciTech Connect (OSTI)

Advanced z-pinch accelerators require precise timing of multiple mega-ampere drivers to deliver terawatt power. The triggering of these drivers is now largely initiated by laser ionization of gas switches. In this paper, we discuss detailed fully kinetic simulation of the Z laser-triggered gas switch involving detailed finite-difference time-domain particle-in-cell Monte Carlo modeling of the trigger section of the switch. Other components of the accelerator from the Marx bank through the pulse-forming line are described as circuit elements. The simulations presented here build on a recently developed model of electro-negative gas breakdown and streamer propagation that included photons produced from de-excited neutrals. New effects include multi-photon ionization of the gas in a prescribed laser field. The simulations show the sensitivity of triggering to laser parameters including focal plane within the anode-cathode gap of the trigger section of the switch, intensity at focus, and laser pulse length. Detailed electromagnetic simulations of the trigger section with circuit modeling of the upstream and downstream components are largely in agreement with Z data and demonstrate a new capability.

Welch, D. R.; Rose, D. V.; Thoma, C.; Clark, R. E.; Miller, C.; Madrid, E. A.; Zimmerman, W. R. [Voss Scientific, LLC, Albuquerque, New Mexico 87108 (United States)] [Voss Scientific, LLC, Albuquerque, New Mexico 87108 (United States); Rambo, P. K.; Schwarz, J.; Savage, M.; Atherton, B. W. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1196 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-1196 (United States)

2013-08-15T23:59:59.000Z

127

JOURNAL OF MATERIALS SCIENCE 31 (1996) 2801 2805 Laser ablation of diamond fibres and a diamond fibre  

E-Print Network [OSTI]

.been embedded in Ti-6A1-4V alloy to produce a diamond fibre-reinforced composite. Both the fibres and a diamond fibre-reinforced titanium alloy composite. 2. Experimental procedure Fibres have been made of a diamond-coated fibre after localized ablations is shown tn Fig. 1. The areas of the diamond surface

Bristol, University of

128

Ablation of film stacks in solar cell fabrication processes  

DOE Patents [OSTI]

A dielectric film stack of a solar cell is ablated using a laser. The dielectric film stack includes a layer that is absorptive in a wavelength of operation of the laser source. The laser source, which fires laser pulses at a pulse repetition rate, is configured to ablate the film stack to expose an underlying layer of material. The laser source may be configured to fire a burst of two laser pulses or a single temporally asymmetric laser pulse within a single pulse repetition to achieve complete ablation in a single step.

Harley, Gabriel; Kim, Taeseok; Cousins, Peter John

2013-04-02T23:59:59.000Z

129

Laser ablation-inductively coupled plasma-mass spectrometry: Examinations of the origins of polyatomic ions and advances in the sampling of particulates  

SciTech Connect (OSTI)

This dissertation provides a general introduction to Inductively coupled plasma-mass spectrometry (ICP-MS) and laser ablation (LA) sampling, with an examination of analytical challenges in the employment of this technique. It discusses the origin of metal oxide ions (MO+) in LA-ICP-MS, as well as the effect of introducing helium and nitrogen to the aerosol gas flow on the formation of these polyatomic interferences. It extends the study of polyatomic ions in LA-ICP-MS to metal argide (MAr+) species, an additional source of possible significant interferences in the spectrum. It describes the application of fs-LA-ICP-MS to the determination of uranium isotope ratios in particulate samples.

Witte, Travis

2011-11-30T23:59:59.000Z

130

Peak effect in laser ablated DyBa2Cu3O7-d films at microwave frequencies at subcritical currents  

E-Print Network [OSTI]

In this paper we report the observation of a peak in the microwave surface resistance (at frequencies ~10GHz) of laser ablated DyBa2Cu3O7-d films in magnetic field ranging from 2 to 9kOe (||c) close to the superconducting transition temperature (Tc(H)). The exact nature of peak is sample dependent but it follows a general behaviour. The peak shifts to lower temperature when the magnetic field is increased. It has strong frequency dependence and the peak is pronounced at frequencies close to the depinning frequency of the flux line lattice. From the observed temperature and field dependence we argue that this peak is associated with the order disorder transition of the flux line lattice close to Tc(H).

A. R. Bhangale; P. Raychaudhuri; T. Banerjee; R. Pinto; V. S. Shirodhkar

2000-11-16T23:59:59.000Z

131

ablation ambient pressure: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

molecular imaging by laser ablation electrospray ionization mass spectrometry with ion mobility separation Chemistry Websites Summary: mouse brain sections) were imaged under...

132

E-Print Network 3.0 - ablation technique possibilities Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of ablation mechanisms is possible, depending on the wavelength, pulse duration, and intensity of the laser... :sapphire laser.24 Future work will evaluate several possible...

133

Oxygen Discharge and Post-Discharge Kinetics Experiments and Modeling for the Electric Oxygen-Iodine Laser System  

E-Print Network [OSTI]

Oxygen Discharge and Post-Discharge Kinetics Experiments and Modeling for the Electric Oxygen a low-pressure oxygen/helium/nitric oxide discharge. In the electric discharge oxygen-iodine laser (ElectricOIL) the discharge production of atomic oxygen, ozone, and other excited species adds levels

Carroll, David L.

134

Analysis of the structure, configuration, and sizing of Cu and Cu oxide nanoparticles generated by fs laser ablation of solid target in liquids  

SciTech Connect (OSTI)

We report on the analysis of structure, configuration, and sizing of Cu and Cu oxide nanoparticles (Nps) produced by femtosecond (fs) laser ablation of solid copper target in liquids. Laser pulse energy ranged between 500 {mu}J and 50 {mu}J. Water and acetone were used to produce the colloidal suspensions. The study was performed through optical extinction spectroscopy using Mie theory to fit the full experimental spectra, considering free and bound electrons size dependent contributions to the metal dielectric function. Raman spectroscopy and AFM technique were also used to characterize the sample. Considering the possible oxidation of copper during the fabrication process, two species (Cu and Cu{sub 2}O) arranged in two structures (bare core or core-shell) and in two configuration types (Cu-Cu{sub 2}O or Cu{sub 2}O-Cu) were considered for the fitting depending on the laser pulse energy and the surrounding media. For water at high energy, it can be observed that a Cu-Cu{sub 2}O configuration fits the experimental spectra of the colloidal suspension, while for decreasing energy and below a certain threshold, a Cu{sub 2}O-Cu configuration needs to be included for the optimum fit. Both species coexist for energies below 170 {mu}J for water. On the other hand, for acetone at high energy, optimum fit of the full spectrum suggests the presence a bimodal Cu-Cu{sub 2}O core-shell Nps distribution while for decreasing energy and below a 70 {mu}J threshold energy value, Cu{sub 2}O-Cu core-shell Nps must be included, together with the former configuration, for the fit of the full spectrum. We discuss possible reasons for the changes in the structural configuration of the core-shell Nps.

Santillan, J. M. J. [Centro de Investigaciones Opticas (CIOp), (CONICET La Plata - CIC) (Argentina); Videla, F. A.; Schinca, D. C.; Scaffardi, L. B. [Centro de Investigaciones Opticas (CIOp), (CONICET La Plata - CIC) (Argentina); Departamento de Ciencias Basicas, Facultad de Ingenieria, UNLP (Argentina); Fernandez van Raap, M. B. [Departamento de Fisica-IFLP, Universidad Nacional de La Plata-CONICET, L. B. Scaffardi: CIOp CC3 (1897) Gonnet, La Plata (Argentina)

2013-04-07T23:59:59.000Z

135

ORIGINAL RESEARCH Noninvasive Measurement of Ablation Crater Size  

E-Print Network [OSTI]

proportional to laser power, whereas crater width and the zone of thermal injury appear to be unrelatedORIGINAL RESEARCH Noninvasive Measurement of Ablation Crater Size and Thermal Injury After CO2 at 10 m resolution, and the thermal disruption after laser ablation were identified by OCT. OCT

Chen, Zhongping

136

Studies of ion kinetic effects in shock-driven inertial confinement fusion implosions at OMEGA and the NIF and magnetic reconnection using laser-produced plasmas at OMEGA  

E-Print Network [OSTI]

Studies of ion kinetic effects during the shock-convergence phase of inertial confinement fusion (ICF) implosions and magnetic reconnection in strongly-driven, laser-produced plasmas have been facilitated by the use of ...

Rosenberg, Michael Jonathan

2014-01-01T23:59:59.000Z

137

Ultrafast Infrared Heating Laser Pulse-Induced Micellization Kinetics of Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) in  

E-Print Network [OSTI]

Ultrafast Infrared Heating Laser Pulse-Induced Micellization Kinetics of Poly(ethylene oxide infrared heating laser pulse (10 ns)-induced temperature jump. The increases in the fluorescenceVersity of Hong Kong, Shatin N.T., Hong Kong ReceiVed June 4, 2007. In Final Form: July 7, 2007 The heating

Liu, Shilin

138

Pulsed laser kinetic studies of liquids under high pressure. Progress report, November 25, 1991--September 18, 1992  

SciTech Connect (OSTI)

A laser flash photolysis kinetic study of 2,2{prime}-bipyridine bidentate chelating ligands with one claw in the first coordination sphere of a molybdenum carbonyl complex has been completed at pressures up to 150 MPa. The reaction mechanism for thermal ring closure is found from activation volumes to change from associative interchange to dissociative interchange as substituents on the 2,2{prime}-bipyridine ligands become bulkier. In a similar study of more rigid, substituted phenanthroline bidentate ligands it was found that substituent bulkiness had little effect on the thermal ring closure mechanism. Stability constants for lithium ion complexes with crown ethers in a room temperature molten salt, fluorescence quantum yields for cresyl violet and several other dyes in solution, and the oxidation of alcohols by OsO{sub 4} have also been investigated.

Eyring, E.M.

1992-09-22T23:59:59.000Z

139

322 IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 37, NO. 3, MARCH 2001 Mechanism Study of Porcine Skin Ablation  

E-Print Network [OSTI]

, biomedical applica- tions of optical radiation, biological tissues, laser ablation, neodymium:YAG lasers identified the Na spectral line at 589 nm in the secondary radiation from the ablated skin sample, spectral analysis. I. INTRODUCTION IN THE progression of less-damaging surgical laser proce- dures

140

Pulsed laser kinetic studies of liquids under high pressure. Progress report, November 29, 1990--November 25, 1991  

SciTech Connect (OSTI)

A high pressure apparatus constructed for measuring the rates of reactions in liquids under pressures ranging from 1 atm to 2000 atm has been used to measure the complexation kinetics of molybdenum hexacarbonyl reacting with 2,2-bipyridine, 4,4{prime}-dimethyl-2-2{prime}-bipyridine and 4,4{prime}-diphenyl-2-2{prime} bipyridine in toluene. Pentacarbonyl reaction intermediates are created by a 10 nsec flash of frequency tripled Nd:YAG laser light. Measured activation volumes for chelate ligand ring closure indicate a change in mechanism from associative interchange to dissociative interchange as steric hindrance increases. A similar high pressure kinetics study of molybdenum carbonyl complexation by several substituted phenanthrolines is now well advanced that indicates that with the more rigid phenanthroline ligands steric effects from bulky substituents have less effect on the ring closure mechanism than in the case of the bipyridine ligands. An experimental concentration dependence of the fluorescence quantum yield of cresyl violet has been harmonized with previously published contradictory reports. Fluorescence of cresyl violet in various solvents and in micellar systems has also been systematically explored.

Eyring, E.M.

1991-11-25T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Final report, Ames Mobile Laboratory Project: The development and operation of instrumentation in a mobile laboratory for in situ, real-time screening and characterization of soils using the laser ablation sampling technique  

SciTech Connect (OSTI)

The main focus of the Ames Laboratory`s Technology Integration Program, TIP, from May 1991 through December 1994 was the development, fabrication, and demonstration of a mobile instrumentation laboratory incorporating rapid in situ sampling systems for safe, rapid, and cost effective soil screening/characterization. The Mobile Demonstration Laboratory for Environmental Screening Technologies, MDLEST, containing the analysis instrumentation, along with surface and subsurface sampling probe prototypes employing the laser ablation sampling technique were chosen to satisfy the particular surface and subsurface soil characterization needs of the various Department of Energy facilities for determining the extent of heavy metal and radionuclide contamination. The MDLEST, a 44 foot long 5th wheel trailer, is easily configured for the analysis instrumentation and sampling system required for the particular site work. This mobile laboratory contains all of the utilities needed to satisfy the operating requirements of the various instrumentation installed. These utilities include, an electric generator, a chilled water system, process gases, a heating/air conditioning system, and computer monitoring and automatic operating systems. Once the MDLEST arrives at the job site, the instrumentation is aligned and calibration is completed, sampling and analysis operations begin. The sample is acquired, analyzed and the results reported in as little as 10 minutes. The surface sampling probe is used in two modes to acquire samples for analysis. It is either set directly on the ground over the site to be sampled, in situ sampling, or in a special fixture used for calibrating the sampling analysis system with standard soil samples, having the samples brought to the MDLEST. The surface sampling probe was used to in situ sample a flat concrete surface (nondestructively) with the ablated sample being analyzed by the instrumentation in the MDLEST.

Anderson, M.S.; Braymen, S.D.

1995-01-27T23:59:59.000Z

142

Photoluminescent silicon nanocrystals synthesized by reactive laser Daria Riabinina,a  

E-Print Network [OSTI]

Photoluminescent silicon nanocrystals synthesized by reactive laser ablation Daria Riabinina reactive laser ablation in oxygen atmosphere followed by annealing. We observe a strong photoluminescence size, obtained independently by fitting photoluminescence spectra and from x-ray diffraction patterns

143

ccsd-00001265(version1):10Mar2004 Applied Physics A (2004) accepted Silicon clusters produced by femtosecond laser ablation: Non-thermal emission and  

E-Print Network [OSTI]

by using high-energy (6.4 eV) photons [9]. Multiple-charged cluster ions were formed in ps-laser stimulated and investigated using time-of- flight mass spectrometry. Two populations of the Si+ n clusters with different@crmcn.univ-mrs.fr etition rate, up to 30 mJ energy per pulse) operating at 800 nm. A part of the laser beam was selected

Boyer, Edmond

144

Kinetic Electrostatic Electron Nonlinear (KEEN) Waves and their Interactions Driven by the Ponderomotive Force of Crossing Laser Beams  

E-Print Network [OSTI]

We have found, using 1D periodic Vlasov-Poisson simulations, new nonlinear, nonstationary, stable, long lived, coherent structures in phase space, called kinetic electrostatic electron nonlinear (KEEN) waves. Ponderomotively driven for a short period of time, at a particular frequency and wavenumber, well inside the band gap that was thought to exist between electron plasma and electron acoustic wave frequencies, KEEN waves are seen to self-consistently form, and persist for thousands of plasma periods. KEEN waves are comprised of 4 or more significant phase-locked harmonic modes which persist only when driven sufficiently strongly. They also merge when two or more at different frequencies are driven sequentially. However, the final stable KEEN state that emerges is highly sensitive to their relative order of excitation. KEEN waves also interact quite strongly with electron plasma waves (EPW) especially when their harmonics are close to being resonant with the EPW frequency at the same k. The common assumption that whenever sufficiently large amplitude coherent laser energy is present in an unmagnetized plasma, EPWs and IAWs are the only waves with which the electromagnetic energy can interact coherently may require reconsideration.

Bedros Afeyan; K. Won; V. Savchenko; T. Johnston; A. Ghizzo; P. Bertrand

2012-10-30T23:59:59.000Z

145

IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 40, NO. 1, JANUARY 2004 69 Modeling of Skin Tissue Ablation by Nanosecond  

E-Print Network [OSTI]

results. Index Terms--Biological tissues, biomedical applications of optical radiation, laser ablation Ablation by Nanosecond Pulses From Ultraviolet to Near-Infrared and Comparison With Experimental Results in a broad optical spectrum is of fundamental importance to the understanding of laser-tissue interaction

146

Ablation by short optical and X-ray laser pulses N.A. Inogamova, S.I. Anisimova, V.V. Zhakhovskyb,c, A.Ya. Faenovb,d, Yu.V. Petrova,  

E-Print Network [OSTI]

concerning low value of ablation threshold are similar. Low value means high efficiency of short pulse XRL Academy of Sciences, Chernogolovka 142432, Russia; bJoint Institute for High Temperatures, Russian Academy ABSTRACT The paper is devoted to experimental and theoretical studies of ablation of condensed matter

Fominov, Yakov

147

Effects of depositon rate on Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+x] and Bi[sub 2]Sr[sub 1. 6]La[sub 0. 4]CuO[sub 6+x] epitaxial thin film growth by pulsed-laser ablation  

SciTech Connect (OSTI)

Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+x] and Bi[sub 2]Sr[sub 1.6]La[sub 0.4]CuO[sub 6+x] epitaxial films have been grown on (001) MgO and SrTiO[sub 3] substrates at different deposition rates by pulsed-laser ablation(PLA). Surface morphology, crystallinity and superconducting critical temperature of the films depend sensitively on deposition rate even though ablation target composition and substrate temperature were kept almost constant. Scanning election microscopy showed that density of particles generated by PLA is reduced by decreasing the deposition rate. Results show that the highest quality films of the highly anisotropic Bi-based materials are deposited by PLA at a low deposition rate, which results in film growth in a near-equilibrium state. 9 refs, 1 tab, 3 figs.

Zhu, S. (Tennessee Univ., Knoxville, TN (United States). Dept. of Physics and Astronomy); Lowndes, D.H.; Chakoumakos, B.C.; Christen, D.K.; Budai, J.D.; Zheng, X.Y.; Warmack, R.J. (Oak Ridge National Lab., TN (United States))

1993-01-01T23:59:59.000Z

148

Effects of depositon rate on Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+x} and Bi{sub 2}Sr{sub 1.6}La{sub 0.4}CuO{sub 6+x} epitaxial thin film growth by pulsed-laser ablation  

SciTech Connect (OSTI)

Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+x} and Bi{sub 2}Sr{sub 1.6}La{sub 0.4}CuO{sub 6+x} epitaxial films have been grown on (001) MgO and SrTiO{sub 3} substrates at different deposition rates by pulsed-laser ablation(PLA). Surface morphology, crystallinity and superconducting critical temperature of the films depend sensitively on deposition rate even though ablation target composition and substrate temperature were kept almost constant. Scanning election microscopy showed that density of particles generated by PLA is reduced by decreasing the deposition rate. Results show that the highest quality films of the highly anisotropic Bi-based materials are deposited by PLA at a low deposition rate, which results in film growth in a near-equilibrium state. 9 refs, 1 tab, 3 figs.

Zhu, S. [Tennessee Univ., Knoxville, TN (United States). Dept. of Physics and Astronomy; Lowndes, D.H.; Chakoumakos, B.C.; Christen, D.K.; Budai, J.D.; Zheng, X.Y.; Warmack, R.J. [Oak Ridge National Lab., TN (United States)

1993-06-01T23:59:59.000Z

149

E-Print Network 3.0 - ablation enhances age-dependent Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

cells. We analyze a novel layer selective laser ablation process. From a passivating stack composed... of 70 nm silicon nitride that we deposit on top of 35 nm of amorphous...

150

High pressure generation by hot electrons driven ablation  

SciTech Connect (OSTI)

A previous model [Piriz et al. Phys. Plasmas 19, 122705 (2012)] for the ablation driven by the hot electrons generated in collisionless laser-plasma interactions in the framework of shock ignition is revisited. The impact of recent results indicating that for a laser wavelength ? = 0.35 ?m the hot electron temperature ?{sub H} would be independent of the laser intensity I, on the resulting ablation pressure is considered. In comparison with the case when the scaling law ?{sub H}?(I?{sup 2}){sup 1/3} is assumed, the generation of the high pressures needed for driving the ignitor shock may be more demanding. Intensities above 10{sup 17} W/cm{sup 2} would be required for ?{sub H}=25?30 keV.

Piriz, A. R. [E.T.S.I. Industriales, CYTEMA, and Instituto de Investigaciones Energéticas, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)] [E.T.S.I. Industriales, CYTEMA, and Instituto de Investigaciones Energéticas, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Piriz, S. A. [Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid (Spain)] [Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Tahir, N. A. [GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)] [GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)

2013-11-15T23:59:59.000Z

151

Phase field simulation of kinetic superheating and melting of aluminum nanolayer irradiated by pico- and femtosecond laser  

SciTech Connect (OSTI)

Two melting mechanisms are reproduced and quantified for superheating and melting of Al nanolayer irradiated by pico- and femtosecond laser using the advanced phase-field approach coupled with mechanics and a two-temperature model. At heating rates Q?79.04 K/ps induced by picosecond laser, two-sided barrierless surface melting forms two solid-melt interfaces, which meet near the center of a sample. The temperature for surface melting is a linear function, and for complete melting it is a cubic function, of logQ. At Q?300 K/ps induced by femtosecond laser, barrierless and homogeneous melting (without nucleation) at the sample center occurs faster than due to interface propagation. Good agreement with experimental melting time was achieved in a range of 0.95?Q?1290 K/ps without fitting of material parameters.

Seok Hwang, Yong [Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011 (United States)] [Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011 (United States); Levitas, Valery I. [Departments of Aerospace Engineering, Mechanical Engineering, and Material Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)] [Departments of Aerospace Engineering, Mechanical Engineering, and Material Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

2013-12-23T23:59:59.000Z

152

Integrated Kinetic Simulation of Laser-Plasma Interactions, Fast-Electron Generation and Transport in Fast Ignition  

SciTech Connect (OSTI)

We present new results on the physics of short-pulse laser-matter interaction of kilojoule-picosecond pulses at full spatial and temporal scale, using a new approach that combines a 3D collisional electromagnetic Particle-in-Cell code with an MHD-hybrid model of high-density plasma. In the latter, collisions damp out plasma waves, and an Ohm's law with electron inertia effects neglected determines the electric field. In addition to yielding orders of magnitude in speed-up while avoiding numerical instabilities, this allows us to model the whole problem in a single unified framework: the laser-plasma interaction at sub-critical densities, energy deposition at relativistic critical densities, and fast-electron transport in solid densities. Key questions such as the multi-picosecond temporal evolution of the laser energy conversion into hot electrons, the impact of return currents on the laser-plasma interaction, and the effect of self-generated electric and magnetic fields on electron transport will be addressed. We will report applications to current experiments.

Kemp, A; Cohen, B; Divol, L

2009-11-16T23:59:59.000Z

153

Laser Microsurgery in Caenorhabditis elegans Christopher Fang-Yen*  

E-Print Network [OSTI]

CHAPTER 6 Laser Microsurgery in Caenorhabditis elegans Christopher Fang-Yen* , Christopher V. Identifying Cells in C. elegans III. Laser Ablation Theory and Apparatus A. Tissue Damage by Nanosecond and Femtosecond Lasers B. The Laser Apparatus IV. Laser Killing of Cells A. Procedures B. Experimental Design

Fang-Yen, Christopher

154

Kinetic Electrostatic Electron Nonlinear (KEEN) Waves and their Interactions Driven by the Ponderomotive Force of Crossing Laser Beams  

E-Print Network [OSTI]

We have found, using 1D periodic Vlasov-Poisson simulations, new nonlinear, nonstationary, stable, long lived, coherent structures in phase space, called kinetic electrostatic electron nonlinear (KEEN) waves. Ponderomotively driven for a short period of time, at a particular frequency and wavenumber, well inside the band gap that was thought to exist between electron plasma and electron acoustic wave frequencies, KEEN waves are seen to self-consistently form, and persist for thousands of plasma periods. KEEN waves are comprised of 4 or more significant phase-locked harmonic modes which persist only when driven sufficiently strongly. They also merge when two or more at different frequencies are driven sequentially. However, the final stable KEEN state that emerges is highly sensitive to their relative order of excitation. KEEN waves also interact quite strongly with electron plasma waves (EPW) especially when their harmonics are close to being resonant with the EPW frequency at the same k. The common assumptio...

Afeyan, Bedros; Savchenko, V; Johnston, T; Ghizzo, A; Bertrand, P

2012-01-01T23:59:59.000Z

155

Pulsed laser kinetic studies of liquids under high pressure. Final technical report, April 1, 1990--March 31, 1993  

SciTech Connect (OSTI)

Experiments have been developed for measuring the rates of chemical reactions liquids and in supercritical Co{sub 2}. A pulsed (Q-switch) Nd:YAG laser at 355 nm was the pump beam for laser flash photolysis studies of molybdenum and tungsten hexacarbonyls undergoing ligand displacement reactions by bidentate chelating agents such as 2,2{prime}-bipyridine in toluene. Experiments were carried out at 0.1 to 150 MPa. In the case of molybdenum complexes, the reaction mechanism for thermal ring closure is found from activation volumes to change from associative interchange to dissociative interchange as substituents on the 2,2{prime}-bipyridine ligands become bulkier. In a similar study of more rigid, substituted phenanthroline bidentate ligands it was found that substituent bulkiness had little effect on the thermal ring closure mechanism. Similar high pressure flash photolysis experiments with tungsten hexacarbonyl have also been completed. The concentration dependence of the fluorescence and nonradiative decay quantum yields for cresyl violet in several solvent have been reported as well as stability constants for the complexation of lithium ion by four different crown ethers dissolved in a room temperature molten salt.

Eyring, E.M.

1993-06-21T23:59:59.000Z

156

Performance and Controllability of Pulsed Ion Beam Ablation Propulsion  

SciTech Connect (OSTI)

We propose novel propulsion driven by ablation plasma pressures produced by the irradiation of pulsed ion beams onto a propellant. The ion beam ablation propulsion demonstrates by a thin foil (50 {mu}mt), and the flyer velocity of 7.7 km/s at the ion beam energy density of 2 kJ/cm2 adopted by using the Time-of-flight method is observed numerically and experimentally. We estimate the performance of the ion beam ablation propulsion as specific impulse of 3600 s and impulse bit density of 1700 Ns/m2 obtained from the demonstration results. In the numerical analysis, a one-dimensional hydrodynamic model with ion beam energy depositions is used. The control of the ion beam kinetic energy is only improvement of the performance but also propellant consumption. The spacecraft driven by the ion beam ablation provides high performance efficiency with short-pulsed ion beam irradiation. The numerical results of the advanced model explained latent heat and real gas equation of state agreed well with experimental ones over a wide range of the incident ion beam energy density.

Yazawa, Masaru; Buttapeng, Chainarong; Harada, Nobuhiro [Nagaoka University of Technology, Department of Electrical Engineering, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi [Nagaoka University of Technology, Extreme Energy-Density Research Institute, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)

2006-05-02T23:59:59.000Z

157

A Mass Spectrometry Study of Isotope Separation in the Laser Plume  

E-Print Network [OSTI]

1.4.2 Atomic Absorption5.3.2 Atomic Absorption Spectrometry . . . . . . . . . . .ablation and diode laser-atomic absorption spectrometry”,

Suen, Timothy Wu

2012-01-01T23:59:59.000Z

158

Digital multimirror devices for precision laser micromachining  

E-Print Network [OSTI]

DMD LIFT results 24 PMMA donors New 3D printing technology! BiTe semiconductor film New laser 3D printing facility...An ORC breakthrough 75 µm #12;Summary · DMDs are very useful for precise ablation

159

Segmentation and visualization for cardiac ablation procedures  

E-Print Network [OSTI]

In this thesis, we present novel medical image analysis methods to improve planning and outcome evaluation of cardiac ablation procedures. Cardiac ablation is a common medical procedure that consists of burning cardiac ...

Depa, Michal

2011-01-01T23:59:59.000Z

160

Preliminary design and estimate of capital and operating costs for a production scale application of laser decontamination technology  

SciTech Connect (OSTI)

The application of laser ablation technology to the decontamination of radioactive metals, particularly the surfaces of equipment, is discussed. Included is information related to the design, capital and operating costs, and effectiveness of laser ablation technology, based on commercial excimer and Nd:YAG lasers, for the decontamination of production scale equipment.

Pang, Ho-ming; Edelson, M.C.

1994-08-06T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

The mechanism of thin film Si nanomachining using femtosecond laser pulses  

E-Print Network [OSTI]

Femtosecond (fs) laser ablation has been the subject of intense recent research. The pulse time ('width') is shorter than the electronic relaxation time, resulting in a decoupling of the period of laser illumination and ...

Jia, Jimmy Yi-Jie, 1980-

2004-01-01T23:59:59.000Z

162

BBGKY kinetic approach for an e{sup -}e{sup +}{gamma} plasma created from the vacuum in a strong laser-generated electric field: The one-photon annihilation channel  

SciTech Connect (OSTI)

In the present work a closed system of kinetic equations is obtained from the truncation of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for the description of the vacuum creation of an electron-positron plasma and secondary photons due to a strong laser field. This truncation is performed in the Markovian approximation for the one-photon annihilation channel which is accessible due to the presence of the strong external field. Estimates of the photon production rate are obtained for different domains of laser field parameters (frequency {nu} and field strength E). A huge quantity of optical photons of the quasiclassical laser field is necessary to satisfy the conservation laws of the energy and momentum of the constituents (e{sup -}, e{sup +} and {gamma}) in this channel. Since the number of these optical photons corresponds to the order of perturbation theory, a vanishingly small photon production rate results for the optical region and strongly subcritical fields E<laser photons is small and the production rate of photons from the one-photon annihilation process becomes accessible to observations for subcritical fields E < or approx. E{sub c}. In the infrared region the photon distribution has a 1/k spectrum typical for flicker noise.

Blaschke, D. B. [Institute for Theoretical Physics, University of Wroclaw, 50-204 Wroclaw (Poland); Bogoliubov Laboratory for Theoretical Physics, Joint Institute for Nuclear Research, RU - 141980 Dubna (Russian Federation); Dmitriev, V. V.; Smolyansky, S. A. [Department of Physics, Saratov State University, RU - 410026 Saratov (Russian Federation); Roepke, G. [Institut fuer Physik, University of Rostock, D - 18051 Rostock (Germany)

2011-10-15T23:59:59.000Z

163

Nanometer-scale ablation using focused, coherent extreme ultraviolet/soft x-ray light  

DOE Patents [OSTI]

Ablation of holes having diameters as small as 82 nm and having clean walls was obtained in a poly(methyl methacrylate) on a silicon substrate by focusing pulses from a Ne-like Ar, 46.9 nm wavelength, capillary-discharge laser using a freestanding Fresnel zone plate diffracting into third order is described. Spectroscopic analysis of light from the ablation has also been performed. These results demonstrate the use of focused coherent EUV/SXR light for the direct nanoscale patterning of materials.

Menoni, Carmen S. (Fort Collins, CO); Rocca, Jorge J. (Fort Collins, CO); Vaschenko, Georgiy (San Diego, CA); Bloom, Scott (Encinitas, CA); Anderson, Erik H. (El Cerrito, CA); Chao, Weilun (El Cerrito, CA); Hemberg, Oscar (Stockholm, SE)

2011-04-26T23:59:59.000Z

164

The effect of laser wavelength on laser-induced carbon plasma  

SciTech Connect (OSTI)

The effect of laser wavelength on parameters of laser-ablated carbon plume is studied. A theoretical model is applied, which describes the target heating and formation of the plasma and its expansion, and calculations are made for the fundamental and third harmonic of a Nd:YAG laser. The calculated distributions of plasma temperature and electron density in the early phase of expansion show that plasma temperatures are higher in the case of 1064 nm but the electron densities are higher in the case of 355 nm, which is in agreement with experimental findings. It has been shown that while a higher plasma temperature in the case of 1064 nm is the result of stronger plasma absorption, the greater ablation rate in the case of 355 nm results in larger mass density of the ablated plume and hence, in higher electron densities. An additional consequence of a higher ablation rate is slower expansion and smaller dimensions of the plume.

Moscicki, T.; Hoffman, J.; Szymanski, Z. [Institute of Fundamental Technological Research, Pawinskiego 5B, 02-106 Warsaw (Poland)] [Institute of Fundamental Technological Research, Pawinskiego 5B, 02-106 Warsaw (Poland)

2013-08-28T23:59:59.000Z

165

Kinetic-energy-angle differential distribution of photofragments in multiphoton above-threshold dissociation of D{sub 2}{sup +} by linearly polarized 400-nm intense laser fields: Effects of highly excited electronic states  

SciTech Connect (OSTI)

We have performed a detailed calculation of the double-differential angular-kinetic-energy distribution of photofragments in above threshold dissociation (ATD) of D{sub 2}{sup +} from initial vibrational-rotational levels v{sub i}=4,5 and J{sub i}=0,1 in an intense linearly polarized laser field of wavelength 400 nm and intensity 3x10{sup 13} W/cm{sup 2}. The calculation used a time-independent close-coupling (CC) formalism with eight (ten) electronic states included in the basis-set expansion of the molecular wave function. The molecular electronic states included, apart from the two lowest 1s{sigma}{sub g} and 2p{sigma}{sub u} states, were 2p{pi}{sub u}{sup {+-}}, 2s{sigma}{sub g}, 3p{sigma}{sub u}, 3d{sigma}{sub g}, 3d{pi}{sub g}{sup {+-}}, and 4f{sigma}{sub u}. All the higher electronic states dissociate to the atomic state D(2l). A sufficient number of photon absorption channels, n=0-7, and molecular rotational quantum numbers J=0-11 were taken into account to ensure the convergence of the multiphoton ATD probability. Altogether 198 coupled channels had to be considered in the calculation. The calculations reveal signatures of significant ejection of the photodissociation fragments away from the laser polarization direction due to the inclusion of the higher excited electronic states. The ratio of the photofragments perpendicular to and along the polarization axis shows good quantitative agreement with the experimental result. The angular distributions show considerable structures depending on the relative kinetic energies of the photofragments, and the fragments with different kinetic energies show peaks at different dissociation angles.

Khan, Basir Ahamed; Saha, Samir; Bhattacharyya, S. S. [Atomic and Molecular Physics Section, Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)

2006-02-15T23:59:59.000Z

166

Beam current controller for laser ion source  

DOE Patents [OSTI]

The present invention relates to the design and use of an ion source with a rapid beam current controller for experimental and medicinal purposes. More particularly, the present invention relates to the design and use of a laser ion source with a magnetic field applied to confine a plasma flux caused by laser ablation.

Okamura, Masahiro

2014-10-28T23:59:59.000Z

167

Ultrashort-pulse laser generated nanoparticles of energetic materials  

DOE Patents [OSTI]

A process for generating nanoscale particles of energetic materials, such as explosive materials, using ultrashort-pulse laser irradiation. The use of ultrashort laser pulses in embodiments of this invention enables one to generate particles by laser ablation that retain the chemical identity of the starting material while avoiding ignition, deflagration, and detonation of the explosive material.

Welle, Eric J. (Niceville, NM); Tappan, Alexander S. (Albuquerque, NM); Palmer, Jeremy A. (Albuquerque, NM)

2010-08-03T23:59:59.000Z

168

androgen ablation therapy: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Shirley 15 ImageGuided Ex vivo Liver Ablation by Unfocused Ultrasound using Passive Cavitation Detection Engineering Websites Summary: Thermal ablation is widely used for...

169

Review of multi-dimensional large-scale kinetic simulation and physics validation of ion acceleration in relativistic laser-matter interaction  

SciTech Connect (OSTI)

Two new experimental technologies enabled realization of Break-out afterburner (BOA) - High quality Trident laser and free-standing C nm-targets. VPIC is an powerful tool for fundamental research of relativistic laser-matter interaction. Predictions from VPIC are validated - Novel BOA and Solitary ion acceleration mechanisms. VPIC is a fully explicit Particle In Cell (PIC) code: models plasma as billions of macro-particles moving on a computational mesh. VPIC particle advance (which typically dominates computation) has been optimized extensively for many different supercomputers. Laser-driven ions lead to realization promising applications - Ion-based fast ignition; active interrogation, hadron therapy.

Wu, Hui-Chun [Los Alamos National Laboratory; Hegelich, B.M. [Los Alamos National Laboratory; Fernandez, J.C. [Los Alamos National Laboratory; Shah, R.C. [Los Alamos National Laboratory; Palaniyappan, S. [Los Alamos National Laboratory; Jung, D. [Los Alamos National Laboratory; Yin, L [Los Alamos National Laboratory; Albright, B.J. [Los Alamos National Laboratory; Bowers, K. [Guest Scientist of XCP-6; Huang, C. [Los Alamos National Laboratory; Kwan, T.J. [Los Alamos National Laboratory

2012-06-19T23:59:59.000Z

170

Laser-direct-driven quasi-isentropic experiments on aluminum  

SciTech Connect (OSTI)

Laser-direct-driven ramp compression experiments were performed on long temporally shaped laser pulses based on an analytical isentropic compression model. Upper pressure limits, the ablation pressure scaling law, and stress-density curves were studied. The validity of the analytical model used, the ablation pressure scaling law, and the phenomena of missing line-imaging velocity interferometer (VISAR) fringes in the experimental results are discussed.

Xue, Quanxi, E-mail: quanxixue@163.com [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); State Key Laboratory of Laser Interaction with Matter, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Wang, Zhebin; Jiang, Shaoen, E-mail: jiangshn@vip.sina.com; Wang, Feng [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Ye, Xisheng; Liu, Jingru [State Key Laboratory of Laser Interaction with Matter, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)

2014-07-15T23:59:59.000Z

171

Time-resolved spatial distribution of plasma in the ablation of a Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} target by 25?ns KrF ultraviolet laser  

SciTech Connect (OSTI)

We performed radially and longitudinally time-resolved plasma analysis during pulsed laser deposition of Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} thin films. The plasma is shown to be optically thick and strongly non-uniform during the early expansion phase and the resonance line Ba II (455.4?nm) is strongly self-reversed during this time. Plasma temperature and electron density were obtained by comparing experimental emission spectra with the spectral radiance computed for a non-uniform plasma in local thermal equilibrium.

Lagrange, J. F.; Wolfman, J.; Motret, O. [Groupe de Recherche en Matériaux, microélectronique, Acoustique et Nanotechnologies (GREMAN) - UMR 7347 CNRS-CEA, Université François Rabelais de Tours, Faculté des Sciences and Techniques, Parc Grandmont - bât. E – 37200 Tours (France); Hermann, J. [Laboratoire Lasers, Plasmas et Procédés Photoniques (LP3), UMR 6182 CNRS, Aix-Marseille Université, 163 Avenue de Luminy, C. 917 - 13288 Marseille (France)

2014-10-07T23:59:59.000Z

172

Investigating the Kinetics and Structural Effects of Azo Dye Photochemistry Using NMR With In Situ Laser Irradiation and Ab Initio (DFT) Calculations   

E-Print Network [OSTI]

Reversible cis-trans isomerisation of a series of commercially interesting yellow azo dyes has been studied using the technique of Nuclear Magnetic Resonance (NMR) spectroscopy with in situ laser irradiation. Photostationary ...

Gibson, David

2007-01-01T23:59:59.000Z

173

Experimental and theoretical studies of particle generation afterlaser ablation of copper with background gas at atmosphericpressure  

SciTech Connect (OSTI)

Laser ablation has proven to be an effective method for generating nanoparticles; particles are produced in the laser induced vapor plume during the cooling stage. To understand the in-situ condensation process, a series of time resolved light scattering images were recorded and analyzed. Significant changes in the condensation rate and the shape of the condensed aerosol plume were observed in two background gases, helium and argon. The primary particle shape and size distribution were measured using a transmission electron microscope (TEM), a scanning electron microscope (SEM) and a differential mobility analyzer (DMA). The gas dynamics simulation included nucleation and coagulation within the vapor plume, heat and mass transfer from the vapor plume to the background gas, and heat transfer to the sample. The experimental data and the calculated evolution of the shape of the vapor plume showed the same trend for the spatial distribution of the condensed particles in both background gases. The simulated particle size distribution also qualitatively agreed with the experimental data. It was determined that the laser energy, the physical properties of the background gas (conductivity, diffusivity and viscosity), and the shape of the ablation system (ablation chamber and the layout of the sample) have strong effects on the condensation process and the subsequent sizes, shapes and degree of aggregation of the particles.

Wen, Sy-Bor; Mao, Xianglei; Greif, Ralph; Russo, Richard E.

2007-05-31T23:59:59.000Z

174

A Fundamental Study of Laser-Induced Breakdown Spectroscopy Using Fiber Optics for Remote Measurements Of Trace Metals  

SciTech Connect (OSTI)

Develop a fiber-optic imaging probe for microanalysis of solid samples; Design a time-resolved plasma imaging system to measure the development of the LIBS signal; Setup a laboratory system capable of timing two lasers independently, for optimizing and characterizing dual-pulse LIBS; Compare the development of laser-induced plasmas generated with a single laser pulse to the development of laser-induced plasmas generated with a pre-ablation spark prior to sample ablation; Examine the effect of sample matrix on the LIBS signals of elements in different sample matrices; Investigate the effect of excitation wavelength of the ablation beam in pre-ablation spark dual-pulse LIBS experiments; Determine the effect of the physical properties of the sample on the mass of materials ablated.

Scott Goode; S. Michael Angel

2004-01-20T23:59:59.000Z

175

Laser ion source for Columbia Universitys microbeam A.W. Bigelow a,*, G. Randers-Pehrson a  

E-Print Network [OSTI]

Laser ion source for Columbia UniversityÃ?s microbeam A.W. Bigelow a,*, G. Randers-Pehrson a , R High School, NY, USA Available online 29 August 2005 Abstract A laser ion source that will be installed for irradiation experiments with mammalian cells. Through laser ablation the laser ion source can produce heavy

Brenner, David Jonathan

176

Laser expulsion of an organic molecular nanojet from a spatially confined domain  

E-Print Network [OSTI]

laser pulses guided down to the tip by a fiber optic. This method of ablation confinement gives fine of nanometers above a polymer film. The pipette is subsequently irradiated using 3 ns full width at half maximum

Zhigilei, Leonid V.

177

Optical coherence and beamspread in ultrafast-laser pulsetrain-burst hole drilling  

E-Print Network [OSTI]

advantages over single-pulse laser processing of materials and biological tissues. Ultrafast lasers are often material, as is sometimes the case for nanosecond-pulse ablation; further, pulsetrain-bursts of ultrafast of ultrafast laser pulses, at a repetition rate of 1 MHz or greater, is less likely to leave cracks or residual

Marjoribanks, Robin S.

178

Role of Cavitation in Bulk Ultrasound Ablation: A Histologic Study  

E-Print Network [OSTI]

Role of Cavitation in Bulk Ultrasound Ablation: A Histologic Study Chandra Priya Karunakaran, Mark of Cincinnati, Cincinnati, Ohio Abstract. The role of cavitation in bulk ultrasound ablation has been evaluated-ablate probe at 31 W/cm2 for 20 minutes under normal and elevated ambient pressures. A 1 MHz passive cavitation

Mast, T. Douglas

179

High density laser-driven target  

DOE Patents [OSTI]

A high density target for implosion by laser energy composed of a central quantity of fuel surrounded by a high-Z pusher shell with a low-Z ablator-pusher shell spaced therefrom forming a region filled with low-density material.

Lindl, John D. (San Ramon, CA)

1981-01-01T23:59:59.000Z

180

Method for laser induced isotope enrichment  

DOE Patents [OSTI]

Methods for separating isotopes or chemical species of an element and causing enrichment of a desired isotope or chemical species of an element utilizing laser ablation plasmas to modify or fabricate a material containing such isotopes or chemical species are provided. This invention may be used for a wide variety of materials which contain elements having different isotopes or chemical species.

Pronko, Peter P.; Vanrompay, Paul A.; Zhang, Zhiyu

2004-09-07T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

The influence of ambient medium density on laser ablation processes  

SciTech Connect (OSTI)

Interest in high flux transport processes has grown in recent years along with the ability and need to manipulate systems with microscopic length and time scales. These systems present unique engineering challenges. Because the time and length scales associated with these problems are very small, assumptions of local equilibrium, physical and mathematical smoothness of boundaries and the unambiguous definition of thermodynamic fields can not be automatically made, even though they may ultimately be acceptable. Furthermore, the observations are made on macroscopic or integrated scales. The large difference in scales between the temporal evolution of the process and the observation requires careful consideration of the claims made regarding the system`s microscopic, temporal behavior. In particular, consistency of a proposed model with observed results does not guarantee uniqueness, or predictive accuracy for the model. For these reasons, microscale heat transfer systems demand a careful consideration of the framework within which the experimentation and analysis are conducted.

Kilgo, M.M. III

1995-11-01T23:59:59.000Z

182

Generation of Core/shell Nanoparticles with Laser Ablation  

E-Print Network [OSTI]

with different material. We have successfully demonstrated the generation of Sn/Glass, Zn/Glass, Zn/Si, Ge/Si, and Cu/Zn CS-NPs. Key factors affecting the generation of CS-NPs are (1) surface tensions of the constructing materials affecting the associated Gibbs...

Jo, Young Kyong

2012-10-19T23:59:59.000Z

183

Apparatus for the laser ablative synthesis of carbon nanotubes  

DOE Patents [OSTI]

An RF-induction heated side-pumped synthesis chamber for the production of carbon nanotubes. Such an apparatus, while capable of producing large volumes of carbon nanotubes, concurrently provides a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization.

Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA)

2010-02-16T23:59:59.000Z

184

Apparatus for the Laser Ablative Synthesis of Carbon Nanotubes - Energy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth (AOD)ProductssondeadjustsondeadjustAbout theOFFICEAmes LaboratoryAntonya

185

Improvements to Laser Ablation-Inductively Coupled Plasma-Mass...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

for trace elemental analysis of solids. Trace element composition can be useful in forensic applications for matching or attribution studies, in which a material recovered from...

186

Measurements of fuel and ablator R in Symmetry-Capsule implosions with the Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facilitya)  

E-Print Network [OSTI]

Lawrence Livermore National Laboratory, Livermore, California 94550, USA 3 Laboratory for Laser Energetics Spectrometer (MRS) on the National Ignition Facility (NIF) measures the neutron spectrum in the energy range-filled symmetry-capsule implosions at the NIF. DT-fuel R's of 80­140 mg/cm2 and CH-ablator R's of 400­680 mg/cm2

187

Kinetic studies of isoprene reactions with hydroxyl and chlorine radicals  

E-Print Network [OSTI]

Kinetic studies of the isoprene oxidation reactions initiated by the hydroxyl radical OH and the chlorine atom Cl have been investigated using a fast-flow reactor in conjunction with chemical ionization mass spectrometry (CIMS) and using laser...

Suh, Inseon

2012-06-07T23:59:59.000Z

188

Influence of oxygen pressure and aging on LaAlO{sub 3} films grown by pulsed laser deposition on SrTiO{sub 3} substrates  

SciTech Connect (OSTI)

The crystal structures of LaAlO{sub 3} films grown by pulsed laser deposition on SrTiO{sub 3} substrates at oxygen pressure of 10{sup ?3} millibars or 10{sup ?5} millibars, where kinetics of ablated species hardly depend on oxygen background pressure, are compared. Our results show that the interface between LaAlO{sub 3} and SrTiO{sub 3} is sharper when the oxygen pressure is lower. Over time, the formation of various crystalline phases is observed while the crystalline thickness of the LaAlO{sub 3} layer remains unchanged. X-ray scattering as well as atomic force microscopy measurements indicate three-dimensional growth of such phases, which appear to be fed from an amorphous capping layer present in as-grown samples.

Park, Jihwey; Aeppli, Gabriel [London Centre for Nanotechnology, University College London, London WC1H 0AH (United Kingdom); Soh, Yeong-Ah, E-mail: yeongahsoh@gmail.com [London Centre for Nanotechnology, University College London, London WC1H 0AH (United Kingdom); Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom); David, Adrian; Lin, Weinan [Division of Physics and Applied Physics, Nanyang Technological University, Singapore 637371 (Singapore); Wu, Tom [Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)

2014-02-24T23:59:59.000Z

189

Design Calculations For NIF Convergent Ablator Experiments  

SciTech Connect (OSTI)

The NIF convergent ablation tuning effort is underway. In the early experiments, we have discovered that the design code simulations over-predict the capsule implosion velocity and shock flash rhor, but under-predict the hohlraum x-ray flux measurements. The apparent inconsistency between the x-ray flux and radiography data implies that there are important unexplained aspects of the hohlraum and/or capsule behavior.

Olson, R E; Hicks, D G; Meezan, N B; Callahan, D A; Landen, O L; Jones, O S; Langer, S H; Kline, J L; Wilson, D C; Rinderknecht, H; Zylstra, A; Petrasso, R D

2011-10-25T23:59:59.000Z

190

Ion Acceleration by Short Chirped Laser Pulses  

E-Print Network [OSTI]

Direct laser acceleration of ions by short frequency-chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1 % can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies of the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e. higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.

Li, Jian-Xing; Keitel, Christoph H; Harman, Zoltán

2015-01-01T23:59:59.000Z

191

Design of a deuterium and tritium-ablator shock ignition target for the National Ignition Facility  

SciTech Connect (OSTI)

Shock ignition presents a viable path to ignition and high gain on the National Ignition Facility (NIF). In this paper, we describe the development of the 1D design of 0.5 MJ class, all-deuterium and tritium (fuel and ablator) shock ignition target that should be reasonably robust to Rayleigh-Taylor fluid instabilities, mistiming, and hot electron preheat. The target assumes 'day one' NIF hardware and produces a yield of 31 MJ with reasonable allowances for laser backscatter, absorption efficiency, and polar drive power variation. The energetics of polar drive laser absorption require a beam configuration with half of the NIF quads dedicated to launching the ignitor shock, while the remaining quads drive the target compression. Hydrodynamic scaling of the target suggests that gains of 75 and yields 70 MJ may be possible.

Terry, Matthew R.; Perkins, L. John; Sepke, Scott M. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States)

2012-11-15T23:59:59.000Z

192

CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results  

SciTech Connect (OSTI)

Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 {+-} 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 {+-} 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 {+-} 13.6 min and 43.7 {+-} 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 {+-} 8.8 months, local recurrence-free survival was 14.4 {+-} 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 {+-} 16.6 ml/min/1.73 m{sup 2} before RF ablation vs. 47.2 {+-} 11.9 ml/min/1.73 m{sup 2} after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Lemm, G.; Hohenstein, E. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany); Bellemann, N.; Stampfl, U. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Goezen, A. S.; Rassweiler, J. [Clinic for Urology, SLK Kliniken Heilbronn GmbH (Germany); Kauczor, H. U.; Radeleff, B. A. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P. L. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany)

2013-06-15T23:59:59.000Z

193

Emission characteristics and dynamics of C2 from laser produced graphite plasma  

E-Print Network [OSTI]

Emission characteristics and dynamics of C2 from laser produced graphite plasma S. S. Harilal, Riju 1996; accepted for publication 20 December 1996 The emission features of laser ablated graphite plume diagnostic technique. Time resolved optical emission spectroscopy is employed to reveal the velocity

Harilal, S. S.

194

E-Print Network 3.0 - atrial catheter ablation Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

imagingguided radiofrequency atrial ablation and visualization of lesion formation at 3 Tesla Summary: imaging. KEYWORDS Atrial fibrillation; Catheter ablation; Lesion visual-...

195

Plasmadynamics and ionization kinetics of thermionic energy conversion  

SciTech Connect (OSTI)

To reduce the plasma arc-drop, thermionic energy conversion is studied with both analytical and numerical tools. Simplifications are made in both the plasmadynamic and ionization-recombination theories. These are applied to a scheme proposed presently using laser irradiation to enhance the ionization kinetics of the thermionic plasma and thereby reduce the arc-drop. It is also predicted that it is possible to generate the required laser light from a thermionic-type cesium plasma. The analysis takes advantage of theoretical simplifications derived for the ionization-recombination kinetics. It is shown that large laser ionization enhancements can occur and that collisional cesium recombination lasing is expected. To complement the kinetic theory, a numerical method is developed to solve the thermionic plasma dynamics. To combine the analysis of ionization-recombination kinetics with the plasma dynamics of thermionic conversion, a finite difference computer program is constructed. It is capable of solving for both unsteady and steady thermionic converter behavior including possible laser ionization enhancement or atomic recombination lasing. A proposal to improve thermionic converter performance using laser radiation is considered. In this proposed scheme, laser radiation impinging on a thermionic plasma enhances the ionization process thereby raising the plasma density and reducing the plasma arc-drop. A source for such radiation may possibly be a cesium recombination laser operating in a different thermionic converter. The possibility of this being an energy efficient process is discussed. (WHK)

Lawless, J.L. Jr.; Lam, S.H.

1982-02-01T23:59:59.000Z

196

Laser Desorption/Ionization of Transition Metal Atoms and Oxides from Solid Argon Lester Andrews,*, Andreas Rohrbacher, Christopher M. Laperle, and Robert E. Continetti  

E-Print Network [OSTI]

, approximately 10% of the gas sample condensed on the 10K copper plate. For ablation a focused (10 cm f of the laser-ablated metal atoms and O2 in excess argon during condensation at 10 K, have been laser desorbed spectrometry. Adding the C6H5Br chromophore to the Ar/O2 gas mixture also enhanced the metal and oxide ion

Continetti, Robert E.

197

Pathways to Inertial Fusion Energy Laser Direct Drive  

E-Print Network [OSTI]

(NRL) Smoothing by Spectral Dispersion ­ SSD (LLE) DT ice preheated ablator (lower density) DT ice/sec), and ignited by a converging shock produced by high intensity spike in the laser pulse. * R. Betti et al., Phys. Shock ignited target #12;The target has to release enough energy to power the reactor... AND produce

198

An International Pellet Ablation Database L.R. Baylor, A. Geraud*, W.A. Houlberg,  

E-Print Network [OSTI]

An International Pellet Ablation Database L.R. Baylor, A. Geraud*, W.A. Houlberg, D. Frigione+, M of an international pellet ablation database (IPADBASE) that has been assembled to enable studies of pellet ablation theories that are used to describe the physics of an ablating fuel pellet in a tokamak plasma. The database

199

Nonequilibrium quantum kinetics  

SciTech Connect (OSTI)

This paper contains viewgraphs on non-equilibrium quantum kinetics of nuclear reactions at the intermediate and high energy ranges.

Danielewicz, P.

1997-09-22T23:59:59.000Z

200

Hydrodynamic Efficiency of Ablation Propulsion with Pulsed Ion Beam  

SciTech Connect (OSTI)

This paper presents the hydrodynamic efficiency of ablation plasma produced by pulsed ion beam on the basis of the ion beam-target interaction. We used a one-dimensional hydrodynamic fluid compressible to study the physics involved namely an ablation acceleration behavior and analyzed it as a rocketlike model in order to investigate its hydrodynamic variables for propulsion applications. These variables were estimated by the concept of ablation driven implosion in terms of ablated mass fraction, implosion efficiency, and hydrodynamic energy conversion. Herein, the energy conversion efficiency of 17.5% was achieved. In addition, the results show maximum energy efficiency of the ablation process (ablation efficiency) of 67% meaning the efficiency with which pulsed ion beam energy-ablation plasma conversion. The effects of ion beam energy deposition depth to hydrodynamic efficiency were briefly discussed. Further, an evaluation of propulsive force with high specific impulse of 4000s, total impulse of 34mN and momentum to energy ratio in the range of {mu}N/W was also analyzed.

Buttapeng, Chainarong; Yazawa, Masaru; Harada, Nobuhiro [Department of Electrical Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan); Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi [Extreme Energy-Density Research Institute, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan)

2006-05-02T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel beams  

E-Print Network [OSTI]

Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel deposition graphene on glass substrate using femtosecond laser ablation with vortex Bessel beams. The fabricated graphene disks with diameters ranging from 650 nm to 4 µm were characterized by spatially resolved

Paris-Sud XI, Université de

202

Ultrashort pulse high repetition rate laser system for biological tissue processing  

DOE Patents [OSTI]

A method and apparatus are disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment. 8 figs.

Neev, J.; Da Silva, L.B.; Matthews, D.L.; Glinsky, M.E.; Stuart, B.C.; Perry, M.D.; Feit, M.D.; Rubenchik, A.M.

1998-02-24T23:59:59.000Z

203

Ultrashort pulse high repetition rate laser system for biological tissue processing  

DOE Patents [OSTI]

A method and apparatus is disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment.

Neev, Joseph (Laguna Beach, CA); Da Silva, Luiz B. (Danville, CA); Matthews, Dennis L. (Moss Beach, CA); Glinsky, Michael E. (Livermore, CA); Stuart, Brent C. (Fremont, CA); Perry, Michael D. (Livermore, CA); Feit, Michael D. (Livermore, CA); Rubenchik, Alexander M. (Livermore, CA)

1998-01-01T23:59:59.000Z

204

Lasers in Surgery and Medicine 44:805814 (2012) Femtosecond Plasma Mediated Laser Ablation Has  

E-Print Network [OSTI]

of Pediatrics, Radiology, and Microbiology & Immunology, Stanford University School of Medicine, Stanford,4 Christopher H. Contag, PhD,2,5,6Ã? and Derrick C. Wan, MD 1Ã?Ã? 1 Hagey Laboratory for Pediatric Regenerative

Palanker, Daniel

205

atrioventricular node ablation: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

is performed in selected patients with a symptomatic premature ventricular complex (PVC) or PVC-induced cardiomyopathy. Ablation of PVC from the His region has a high risk of...

206

Infrared absorption spectroscopy and chemical kinetics of free radicals  

SciTech Connect (OSTI)

This research is directed at the detection, monitoring, and study of chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. During the last year, infrared kinetic spectroscopy using excimer laser flash photolysis and color-center laser probing has been employed to study the high resolution spectrum of HCCN, the rate constant of the reaction between ethynyl (C{sub 2}H) radical and H{sub 2} in the temperature region between 295 and 875 K, and the recombination rate of propargyl (CH{sub 2}CCH) at room temperature.

Curl, R.F.; Glass, G.P. [Rice Univ., Houston, TX (United States)

1993-12-01T23:59:59.000Z

207

Picoseconds-Laser Modification of Thin Films  

SciTech Connect (OSTI)

The interaction of a Nd:YAG laser, pulse duration of 40 ps, with a titanium nitride (TiN) and tungsten-titanium (W-Ti) thin films deposited at silicon was studied. The peak intensity on targets was up to 1012 W/cm2. Results have shown that the TiN surface was modified, by the laser beam, with energy density of {>=}0.18 J/cm2 ({lambda}laser= 532 nm) as well as of 30.0 J/cm2 ({lambda}laser= 1064 nm). The W-Ti was surface modified with energy density of 5.0 J/cm2 ({lambda}laser= 532 nm). The energy absorbed from the Nd:YAG laser beam is partially converted to thermal energy, which generates a series of effects such as melting, vaporization of molten materials, dissociation and ionization of the vaporized material, appearance of plasma, etc. The following morphological changes of both targets were observed: (i) The appearance of periodic microstructures, in the central zone of the irradiated area, for laser irradiation at 532 nm. Accumulation of great number of laser pulses caused film ablation and silicon modification. (ii) Hole formation on the titanium nitride/silicon target was registered at 1064 nm. The process of the Nd:YAG laser interaction with both targets was accompanied by plasma formation above the target.

Gakovic, Biljana; Trtica, Milan [Institute of Nuclear Sciences 'VINCA' 522, 11001 Belgrade (Serbia and Montenegro); Batani, Dimitri; Desai, Tara; Redaelli, Renato [Dipartimento di Fisica 'G. Occhialini', Universita' degli Studi Milano-Bicocca, Piazza della Scienza 3, Milan 20126 (Italy)

2006-04-07T23:59:59.000Z

208

LLE (Laboratory for Laser Energetics) review  

SciTech Connect (OSTI)

This volume of the LLE Review, covering the period April--June 1990, contains articles in two main sections, Progress in Laser Fusion and Advanced Technology Developments. The first article presents the theoretical interpretation of the glass-ablator cryogenic-implosion experiments recently conducted on OMEGA. It is followed by an article describing the analysis of neutron time-of-flight data taken during DT and DD experiments; and a discussion of the improvements to laser diagnostics that now provide for precise control of the OMEGA laser is given. This paper contains a report on the development of transparent conductive coatings for KDP crystals, and a discussion of the study of the transient-surface Debye-Waller effect in materials irradiated with an ultrafast laser.

Kumpan, S.A. (ed.)

1990-01-01T23:59:59.000Z

209

Composition analysis by scanning femtosecond laser ultraprobing (CASFLU).  

DOE Patents [OSTI]

The composition analysis by scanning femtosecond ultraprobing (CASFLU) technology scans a focused train of extremely short-duration, very intense laser pulses across a sample. The partially-ionized plasma ablated by each pulse is spectrometrically analyzed in real time, determining the ablated material's composition. The steering of the scanned beam thus is computer directed to either continue ablative material-removal at the same site or to successively remove nearby material for the same type of composition analysis. This invention has utility in high-speed chemical-elemental, molecular-fragment and isotopic analyses of the microstructure composition of complex objects, e.g., the oxygen isotopic compositions of large populations of single osteons in bone.

Ishikawa, Muriel Y. (Livermore, CA); Wood, Lowell L. (Simi Valley, CA); Campbell, E. Michael (Danveille, CA); Stuart, Brent C. (Livermore, CA); Perry, Michael D. (Livermore, CA)

2002-01-01T23:59:59.000Z

210

High-quality electron beam from laser wake-field acceleration in laser produced plasma plumes  

SciTech Connect (OSTI)

Generation of highly collimated ({theta}{sub div}{approx}10 mrad), quasi-monoenergetic electron beam with peak energy 12 MeV and charge {approx}50 pC has been experimentally demonstrated from self-guided laser wake-field acceleration (LWFA) in a plasma plume produced by laser ablation of solid nylon (C{sub 12}H{sub 22}N{sub 2}O{sub 2}){sub n} target. A 7 TW, 45 fs Ti:sapphire laser system was used for LWFA, and the plasma plume forming pulse was derived from the Nd:YAG pump laser of the same system. The results show that a reproducible, high quality electron beam could be produced from this scheme which is simple, low cost and has the capability for high repetition rate operation.

Sanyasi Rao, Bobbili; Moorti, Anand; Rathore, Ranjana; Ali Chakera, Juzer; Anant Naik, Prasad; Dass Gupta, Parshotam [Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)] [Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

2013-06-10T23:59:59.000Z

211

E-Print Network 3.0 - ablation system kit Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

The plasma-mediated ablation threshold of the PDMS is analyzed as 4.6 J cm... rate and irradiation pulse energy--on the ablation line width, internal ... Source: Guo, Zhixiong...

212

E-Print Network 3.0 - ablative thermal protection Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of fused silica Summary: is considered as "thermal" ablation because it is caused by the high temperature in the material. On the other... " ablation. Both thermal and non-thermal...

213

High Energy Laser for Space Debris Removal  

SciTech Connect (OSTI)

The National Ignition Facility (NIF) and Photon Science Directorate at Lawrence Livermore National Laboratory (LLNL) has substantial relevant experience in the construction of high energy lasers, and more recently in the development of advanced high average power solid state lasers. We are currently developing new concepts for advanced solid state laser drivers for the Laser Inertial Fusion Energy (LIFE) application, and other high average power laser applications that could become central technologies for use in space debris removal. The debris population most readily addressed by our laser technology is that of 0.1-10 cm sized debris in low earth orbit (LEO). In this application, a ground based laser system would engage an orbiting target and slow it down by ablating material from its surface which leads to reentry into the atmosphere, as proposed by NASA's ORION Project. The ORION concept of operations (CONOPS) is also described in general terms by Phipps. Key aspects of this approach include the need for high irradiance on target, 10{sup 8} to 10{sup 9} W/cm{sup 2}, which favors short (i.e., picoseconds to nanoseconds) laser pulse durations and high energy per pulse ({approx} > 10 kJ). Due to the target's orbital velocity, the potential duration of engagement is only of order 100 seconds, so a high pulse repetition rate is also essential. The laser technology needed for this application did not exist when ORION was first proposed, but today, a unique combination of emerging technologies could create a path to enable deployment in the near future. Our concepts for the laser system architecture are an extension of what was developed for the National Ignition Facility (NIF), combined with high repetition rate laser technology developed for Inertial Fusion Energy (IFE), and heat capacity laser technology developed for military applications. The 'front-end' seed pulse generator would be fiber-optics based, and would generate a temporally, and spectrally tailored pulse designed for high transmission through the atmosphere, as well as efficient ablative coupling to the target. The main amplifier would use either diode-pumped or flashlamp-pumped solid state gain media, depending on budget constraints of the project. A continuously operating system would use the gas-cooled amplifier technology developed for Mercury, while a burst-mode option would use the heat capacity laser technology. The ground-based system that we propose is capable of rapid engagement of targets whose orbits cross over the site, with potential for kill on a single pass. Very little target mass is ablated per pulse so the potential to create additional hazardous orbiting debris is minimal. Our cost estimates range from $2500 to $5000 per J depending on choices for laser gain medium, amplifier pump source, and thermal management method. A flashlamp-pumped, Nd:glass heat-capacity laser operating in the burst mode would have costs at the lower end of this spectrum and would suffice to demonstrate the efficacy of this approach as a prototype system. A diode-pumped, gas-cooled laser would have higher costs but could be operated continuously, and might be desirable for more demanding mission needs. Maneuverability can be incorporated in the system design if the additional cost is deemed acceptable. The laser system would need to be coupled with a target pointing and tracking telescope with guide-star-like wavefront correction capability.

Barty, C; Caird, J; Erlandson, A; Beach, R; Rubenchik, A

2009-10-30T23:59:59.000Z

214

LLE Quarterly Report (July-September 1999)[Library for Laser Energetics  

SciTech Connect (OSTI)

This volume of the LLE Review, covering the period July-September 1999, features a theoretical analysis of a process that generates mass perturbations of an imploding target driven by modulated laser illumination. The process, referred to as laser imprint, impacts the integrity of the shell during direct-drive implosions, potentially quenching target performance. In this article V. N. Goncharov, J. A. Delettrez, S. Skupsky, and R. P. J. Town present a model of the generation of mass perturbations and analyze the mass perturbation growth due to nonuniform ablation pressure. Stabilizing mechanisms of thermal conduction smoothing and mass ablation are shown to suppress the acceleration perturbation, and mass ablation is also shown to impact velocity perturbations. The model predicts that a direct-drive cryogenic NIF target will remain intact during the implosion when l-Thz SSD beam smoothing is used.

NONE

2000-01-07T23:59:59.000Z

215

E-Print Network 3.0 - ablation mass spectroscopy Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

implants into rat livers after radiofrequency ablation were quantified by atomic absorption spectroscopy... Local carboplatin delivery and tissue distribution in...

216

Time-resolved wavelength modulation spectroscopy measurements of HO2 kinetics  

E-Print Network [OSTI]

of the hydroperoxyl radical HO2 in a laser photolysis and long-path absorption pump-probe kinetics reactor with a near with a 1.5- m diode laser directly modulated at 5 MHz. The measured 2f WMS signal is calibrated by direct ab- sorbance of 1% or less , and the proportionality con- stant is established easily by comparison

217

Plasmadynamics and ionization kinetics of thermionic energy conversion  

SciTech Connect (OSTI)

To reduce the plasma arc-drop, thermionic energy conversion is studied with both analytical and numerical tools. Simplifications are made in both the plasmadynamic and ionization-recombination theories. These are applied to a scheme proposed presently using laser irradiation to enhance the ionization kinetics of the thermionic plasma and thereby reduce the arc-drop. It is also predicted that it is possible to generate the required laser light from a thermionic-type Cesium plasma. The analysis takes advantage of theoretical simplifications derived for the ionization-recombination kinetics. It is shown that large laser ionization enhancements can occur and that collisional Cesium recombination lasing is expected. To complement the kinetic theory, a numerical method is developed to solve the thermionic plasma dynamics. The effects of the complete system of electron-atom inelastic collisions on the ionization-recombination problem are shown to reduce to a system nearly as simple as the well-known one-quantum approximation. To combine the above analysis of ionization-recombination kinetics with the plasma dynamics of thermionic conversion, a finite difference computer program is constructed. Using the above developments, a proposal to improve thermionic converter performance using laser radiation is considered. In this proposed scheme, laser radiation impinging on a thermionic plasma enhances the ionization process thereby raising the plasma density and reducing the plasma arc-drop. A source for such radiation may possibly be a Cesium recombination laser operating in a different thermionic converter. The possibility of this being an energy efficient process is discussed.

Lawless, J.L. Jr.

1981-01-01T23:59:59.000Z

218

Towards Optimization of Probe Placement for Radio-Frequency Ablation  

E-Print Network [OSTI]

's electric potential and of the steady state of the heat distribution during RF ablation. The optimization with mono- or bipolar systems: A probe, connected to an electric generator, is placed inside the malignant tissue, such that an electric current flows through the body and heats the tissue near the probe up

Preusser, Tobias

219

ablative materials: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ablative materials First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Photochemical induced effects in...

220

Measurements of Cavitation Dose, Echogenicity, and Temperature during Ultrasound Ablation  

E-Print Network [OSTI]

Measurements of Cavitation Dose, Echogenicity, and Temperature during Ultrasound Ablation T traces from the array, time-domain signals received by a 1 MHz, unfocused passive cavitation detector signals received by the array. Cavitation dose was quantified from the spectra of signals measured

Mast, T. Douglas

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Page 1Laser Safety Training Laser Institute of America Laser Safety Laser Institute of America  

E-Print Network [OSTI]

Page 1Laser Safety Training © Laser Institute of America 1 Laser Safety © Laser Institute of America Laser Safety: Hazards, Bioeffects, and Control Measures Laser Institute of America Gus Anibarro Education Manager 2Laser Safety © Laser Institute of America Laser Safety Overview Laser Safety Accidents

Farritor, Shane

222

Laser Telecommunication timeLaser beam  

E-Print Network [OSTI]

Laser Telecommunication Experiment Laser time Laser beam intensity timeLaser beam Laser battery Laser connected to a circuit without a modulator. Bottom graph illustrates what happen when a modulating signal is superimposed to the DC voltage driving the laser Laser beam intensity DC Input voltage DC

La Rosa, Andres H.

223

Lung Tumor Radiofrequency Ablation: Where Do We Stand?  

SciTech Connect (OSTI)

Today, radiofrequency ablation (RFA) of primary and metastatic lung tumor is increasingly used. Because RFA is most often used with curative intent, preablation workup must be a preoperative workup. General anesthesia provides higher feasibility than conscious sedation. The electrode positioning must be performed under computed tomography for sake of accuracy. The delivery of RFA must be adapted to tumor location, with different impedances used when treating tumors with or without pleural contact. The estimated rate of incomplete local treatment at 18 months was 7% (95% confidence interval, 3-14) per tumor, with incomplete treatment depicted at 4 months (n = 1), 6 months (n = 2), 9 months (n = 2), and 12 months (n = 2). Overall survival and lung disease-free survival at 18 months were, respectively, 71 and 34%. Size is a key point for tumor selection because large size is predictive of incomplete local treatment and poor survival. The ratio of ablation volume relative to tumor volume is predictive of complete ablation. Follow-up computed tomography that relies on the size of the ablation zone demonstrates the presence of incomplete ablation. Positron emission tomography might be an interesting option. Chest tube placement for pneumothorax is reported in 8 to 12%. Alveolar hemorrhage and postprocedure hemoptysis occurred in approximately 10% of procedures and rarely required specific treatment. Death was mostly related to single-lung patients and hilar tumors. No modification of forced expiratory volume in the first second between pre- and post-RFA at 2 months was found. RFA in the lung provides a high local efficacy rate. The use of RFA as a palliative tool in combination with chemotherapy remains to be explored.

Baere, Thierry de, E-mail: debaere@igr.fr [Institut Gustave Roussy, Department of Interventional Radiology (France)

2011-04-15T23:59:59.000Z

224

Fast neutron production from lithium converters and laser driven protons  

SciTech Connect (OSTI)

Experiments to generate neutrons from the {sup 7}Li(p,n){sup 7}Be reaction with 60 J, 180 fs laser pulses have been performed at the Texas Petawatt Laser Facility at the University of Texas at Austin. The protons were accelerated from the rear surface of a thin target membrane using the target-normal-sheath-acceleration mechanism. The neutrons were generated in nuclear reactions caused by the subsequent proton bombardment of a pure lithium foil of natural isotopic abundance. The neutron energy ranged up to 2.9 MeV. The total yield was estimated to be 1.6 × 10{sup 7} neutrons per steradian. An extreme ultra-violet light camera, used to image the target rear surface, correlated variations in the proton yield and peak energy to target rear surface ablation. Calculations using the hydrodynamics code FLASH indicated that the ablation resulted from a laser pre-pulse of prolonged intensity. The ablation severely limited the proton acceleration and neutron yield.

Storm, M.; Jiang, S.; Wertepny, D.; Orban, C.; Morrison, J.; Willis, C.; McCary, E.; Balencourt, P.; Snyder, J.; Chowdhury, E.; Freeman, R. R.; Akli, K. [Department of Physics, The Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio 43210 (United States)] [Department of Physics, The Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio 43210 (United States); Bang, W.; Gaul, E.; Dyer, G.; Ditmire, T. [Department of Physics, Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas 78712 (United States)] [Department of Physics, Center for High Energy Density Science, C1510, University of Texas at Austin, Austin, Texas 78712 (United States)

2013-05-15T23:59:59.000Z

225

Laser microphone  

DOE Patents [OSTI]

A microphone for detecting sound pressure waves includes a laser resonator having a laser gain material aligned coaxially between a pair of first and second mirrors for producing a laser beam. A reference cell is disposed between the laser material and one of the mirrors for transmitting a reference portion of the laser beam between the mirrors. A sensing cell is disposed between the laser material and one of the mirrors, and is laterally displaced from the reference cell for transmitting a signal portion of the laser beam, with the sensing cell being open for receiving the sound waves. A photodetector is disposed in optical communication with the first mirror for receiving the laser beam, and produces an acoustic signal therefrom for the sound waves.

Veligdan, James T. (Manorville, NY)

2000-11-14T23:59:59.000Z

226

Dynamics of femtosecond laser produced tungsten nanoparticle plumes  

SciTech Connect (OSTI)

We investigated the expansion features of femtosecond laser generated tungsten nanoparticle plumes in vacuum. Fast gated images showed distinct two components expansion features, viz., plasma and nanoparticle plumes, separated by time of appearance. The persistence of plasma and nanoparticle plumes are ?500 ns and ?100 ?s, respectively, and propagating with velocities differed by 25 times. The estimated temperature of the nanoparticles showed a decreasing trend with increasing time and space. Compared to low-Z materials (e.g., Si), ultrafast laser ablation of high-Z materials like W provides significantly higher nanoparticle yield. A comparison between the nanoparticle plumes generated by W and Si is also discussed along with other metals.

Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Farid, N. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States) [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); School of Physics and Optical Engineering, Dalian University of Technology, Dalian 116024 (China); Kozhevin, V. M. [Ioffe Physics Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)] [Ioffe Physics Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)

2013-11-28T23:59:59.000Z

227

Erbium hydride decomposition kinetics.  

SciTech Connect (OSTI)

Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

Ferrizz, Robert Matthew

2006-11-01T23:59:59.000Z

228

Spectroscopy and kinetics of combustion gases at high temperatures  

SciTech Connect (OSTI)

This program involves two complementary activities: (1) development and application of cw ring dye laser absorption methods for sensitive detection of radical species and measurement of fundamental spectroscopic parameters at high temperatures; and (2) shock tube studies of reaction kinetics relevant to combustion. Species currently under investigation in the spectroscopic portion of the research include NO and CH{sub 3}; this has necessitated the continued operated at wavelengths in the range 210-230 nm. Shock tube studies of reaction kinetics currently are focussed on reactions involving CH{sub 3} radicals.

Hanson, R.K.; Bowman, C.T. [Stanford Univ., CA (United States)

1993-12-01T23:59:59.000Z

229

Kinetic theory viscosity  

E-Print Network [OSTI]

We show how the viscous evolution of Keplerian accretion discs can be understood in terms of simple kinetic theory. Although standard physics texts give a simple derivation of momentum transfer in a linear shear flow using kinetic theory, many authors, as detailed by Hayashi & Matsuda 2001, have had difficulties applying the same considerations to a circular shear flow. We show here how this may be done, and note that the essential ingredients are to take proper account of, first, isotropy locally in the frame of the fluid and, second, the geometry of the mean flow.

C. J. Clarke; J. E. Pringle

2004-03-17T23:59:59.000Z

230

Molecular Beam Kinetics | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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231

Laser device  

DOE Patents [OSTI]

A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

Scott, Jill R. (Idaho Falls, ID); Tremblay, Paul L. (Idaho Falls, ID)

2007-07-10T23:59:59.000Z

232

Ablative thermal management structural material on the hypersonic vehicles  

SciTech Connect (OSTI)

A hypersonic vehicle is designed to fly at high Mach number in the earth`s atmosphere that will result in higher aerodynamic heating loads on specific areas of the vehicle. A thermal protection system is required for these areas that may exceed the operating temperature limit of structural materials. This paper delineates the application of ablative material as the passive type of thermal protection system for the nose or wing leading edges. A simplified quasi-steady-state one-dimensional computer model was developed to evaluate the performance and thermal design of a leading edge. The detailed description of the governing mathematical equations and results are presented. This model provides a quantitative information to support the design estimate, performance optimization, and assess preliminary feasibility of using ablation as a design approach.

Shortland, H.; Tsai, C. [Rockwell International Corporation, Seal Beach, CA (United States)

1995-09-01T23:59:59.000Z

233

Laparoscopic Ultrasound-Guided Radiofrequency Ablation of Uterine Fibroids  

SciTech Connect (OSTI)

Four patients with symptomatic uterine fibroids measuring less than 6 cm underwent laparoscopic ultrasound-guided radiofrequency ablation (RFA) using multiprobe-array electrodes. Follow-up of the treated fibroids was performed with gadolinium-enhanced magnetic resonance imaging (MRI) and patients' symptoms were assessed by telephone interviews. The procedure was initially technically successful in 3 of the 4 patients and MRI studies at 1 month demonstrated complete fibroid ablation. Symptom improvement, including a decrease in menstrual bleeding and pain, was achieved in 2 patients at 3 months. At 7 months, 1 of these 2 patients experienced symptom worsening which correlated with recurrent fibroid on MRI. The third, initially technically successfully treated patient did not experience any symptom relief after the procedure and was ultimately diagnosed with adenomyosis. Our preliminary results suggest that RFA is a technically feasible treatment for symptomatic uterine fibroids in appropriately selected patients.

Milic, Andrea [University of Toronto, Department of Medical Imaging (Canada); Asch, Murray R. [Lakeridge Health Corporation, Department of Diagnostic Radiology (Canada)], E-mail: masch@lakeridgehealth.on.ca; Hawrylyshyn, Peter A.; Allen, Lisa M. [Mount Sinai Hospital, Department of Obstetrics and Gynecology (Canada); Colgan, Terence J. [Mount Sinai Hospital, Department of Pathology (Canada); Kachura, John R. [Toronto General Hospital, Department of Diagnostic Imaging (Canada); Hayeems, Eran B. [Mount Sinai Hospital, Department of Diagnostic Imaging (Canada)

2006-08-15T23:59:59.000Z

234

Comparison of laser-based mitigation of fused silica surface damage using mid- versus far-infrared lasers  

SciTech Connect (OSTI)

Laser induced growth of optical damage can limit component lifetime and therefore operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, they quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {micro}m) versus far-IR (10.6 {micro}m) lasers in mitigating damage growth on fused silica surfaces. The non-linear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda} = 4.6 {micro}m, while far-IR laser heating is well-described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on infrared radiometry, as well as sub-surface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally-ablative conditions. Based on their FOM, they show that for cracks up to at least 500 {micro}m in depth, mitigation with a 4.6 {micro}m mid-IR laser is more efficient than mitigation with a 10.6 {micro}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {micro}m in depth.

Yang, S T; Matthews, M J; Elhadj, S; Cooke, D; Guss, G M; Draggoo, V G; Wegner, P J

2009-12-16T23:59:59.000Z

235

Focal Hydrothermal Ablation: Preliminary Investigation of a New Concept  

SciTech Connect (OSTI)

PurposeTo determine whether focal tissue ablation is possible with interstitial instillation of steam.MethodsFresh swine livers were used. Through a 20 gauge needle, steam was instilled every 5 s, 3 (n = 5), 6 (n = 5), 9 (n = 5), or 12 (n = 5 + 5) times in a liver lobe. The ablated zones were sectioned parallel (n = 20) or perpendicular (n = 5) to the needle track. The longitudinal long and short axis diameters, or transverse long and short axis diameters of areas with discoloration on macroscopic examination, were measured. The experiment was repeated in vivo on a pig. Steam instillation was performed once every 5 s for 5 min in the liver (n = 3) and in muscle (n = 4), and temperature changes at three neighboring sites were monitored. Long and short axis diameters of the discolored areas were measured.ResultsA well-defined area of discoloration was invariably present at the site of steam instillation. The median longitudinal long axis diameter were 2.0, 2.5, 2.5, and 3.5 cm for 3, 6, 9, and 12 steam instillations in vitro, while median short axis diameters were 1.0, 1.5, 1.5, and 1.5 cm, respectively. Six attempts at ablation in vivo could be successfully completed. The long axis diameters of the ablated zones in the liver were 7.0 and 8.0 cm, while in muscle it ranged from 5.5 to 7.0 cm.ConclusionInstillation of steam in the liver in vitro and in vivo, and in muscle in vivo rapidly leads to circumscribed zones of coagulation necrosis.

Roy, Sumit, E-mail: sumit.roy@online.no [Stavanger University Hospital, Department of Radiology (Norway)

2013-08-01T23:59:59.000Z

236

Metal-like self-organization of periodic nanostructures on silicon and silicon carbide under femtosecond laser pulses  

SciTech Connect (OSTI)

Periodic structures were generated on Si and SiC surfaces by irradiation with femtosecond laser pulses. Self-organized structures with spatial periodicity of approximately 600?nm appear on silicon and silicon carbide in the laser fluence range just above the ablation threshold and upon irradiation with a large number of pulses. As in the case of metals, the dependence of the spatial periodicity on laser fluence can be explained by the parametric decay of laser light into surface plasma waves. The results show that the proposed model might be universally applicable to any solid state material.

Gemini, Laura [Advanced Research Center for beam Science, Institute for Chemical Research, Kyoto University, 611-0011 Kyoto (Japan); Department of Physics, Graduate School of Science, Kyoto University, 606-85802 Kyoto (Japan); FNSPE, Czech Technical University in Prague, 11519 Prague (Czech Republic); HiLASE Project, Institute of Physics, ASCR, 18221 Prague (Czech Republic); Hashida, Masaki; Shimizu, Masahiro; Miyasaka, Yasuhiro; Inoue, Shunsuke; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for beam Science, Institute for Chemical Research, Kyoto University, 611-0011 Kyoto (Japan); Department of Physics, Graduate School of Science, Kyoto University, 606-85802 Kyoto (Japan); Limpouch, Jiri [FNSPE, Czech Technical University in Prague, 11519 Prague (Czech Republic); Mocek, Tomas [HiLASE Project, Institute of Physics, ASCR, 18221 Prague (Czech Republic)

2013-11-21T23:59:59.000Z

237

LLNL Chemical Kinetics Modeling Group  

SciTech Connect (OSTI)

The LLNL chemical kinetics modeling group has been responsible for much progress in the development of chemical kinetic models for practical fuels. The group began its work in the early 1970s, developing chemical kinetic models for methane, ethane, ethanol and halogenated inhibitors. Most recently, it has been developing chemical kinetic models for large n-alkanes, cycloalkanes, hexenes, and large methyl esters. These component models are needed to represent gasoline, diesel, jet, and oil-sand-derived fuels.

Pitz, W J; Westbrook, C K; Mehl, M; Herbinet, O; Curran, H J; Silke, E J

2008-09-24T23:59:59.000Z

238

Laser micro-processing of silicon using nanosecond pulse shaped fibre laser at 1 ?m wavelength  

E-Print Network [OSTI]

). ............................................................................... 11 Figure 2.2(a): Schematic and (b) SEM image of 19.8% efficient multicrystalline silicon solar cell with “honeycomb” surface texturing (Zhao, Wang et al. 1998). (c) The “inverted pyramid” texture on the top surface (Zhao, Wang et al. 1995). (d) A... is 40 µm (Tan 2006). (c): SEM image of silicon machined by frequency tripled Nd: YAG laser (355 nm) followed by cleaning in the KOH solution (Chen and Darling 2005). (d) Profiles and SEM images (×1.5 k) of ablated a-Si under different irradiation...

Li, Kun

2012-06-12T23:59:59.000Z

239

Fully-automatic laser welding and micro-sculpting with universal in situ inline coherent imaging  

E-Print Network [OSTI]

Though new affordable high power laser technologies make possible many processing applications in science and industry, depth control remains a serious technical challenge. Here we show that inline coherent imaging, with line rates up to 312 kHz and microsecond-duration capture times, is capable of directly measuring laser penetration depth in a process as violent as kW-class keyhole welding. We exploit ICI's high speed, high dynamic range and robustness to interference from other optical sources to achieve fully automatic, adaptive control of laser welding as well as ablation, achieving micron-scale sculpting in vastly different heterogeneous biological materials.

Webster, Paul J L; Ji, Yang; Galbraith, Christopher M; Kinross, Alison W; Van Vlack, Cole; Fraser, James M

2014-01-01T23:59:59.000Z

240

Femtosecond laser-induced asymmetric large scale waves on gold surfaces  

SciTech Connect (OSTI)

With femtosecond (fs) pulse irradiation, we investigate the morphological evolution of a unique type of fs laser-induced periodic surface structure, called nanostructure-covered large scale waves (NC-LSWs), covered by iterating stripe patterns of nanostructures and microstructures with a period of tens of microns. By monitoring the morphological profile of NC-LSWs following fs laser heating of Au, we show that the NC-LSWs are highly asymmetrically formed and propagate on a gold surface. We believe that the selective laser ablation of Au surface and the subsequent mass transfer of liquid Au following nonuniform energy deposition result in the asymmetric NC-LSW propagation on metals.

Yong Hwang, Taek; Guo, Chunlei [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)

2012-07-09T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Laser ignition  

DOE Patents [OSTI]

In the apparatus of the invention, a first excitation laser or other excitation light source capable of producing alternating beams of light having different wavelengths is used in tandem with one or more ignitor lasers to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using the single remote excitation light source for pumping one or more small lasers located proximate to one or more fuel combustion zones with alternating wavelengths of light.

Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

2002-01-01T23:59:59.000Z

242

E-Print Network 3.0 - ablation assisted resonance Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

enhancement (LGE) mag- netic resonance imaging (MRI) immediately post-ablation (IPA... enhancement MRI magnetic resonance imaging NE nonenhancing RF radiofrequency RFA...

243

ablation multi-collector inductively: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

mass spectrometry (ICP-MS). A compact computer Chen, Zhongxing 14 Measurements of Cavitation Dose, Echogenicity, and Temperature during Ultrasound Ablation Biology and Medicine...

244

E-Print Network 3.0 - ablation therapeutics based Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of the thermal ablation defect based on ... Source: Mast, T. Douglas - Department of Biomedical Engineering, University of Cincinnati Collection: Biology and Medicine ; Engineering...

245

Improving alternative fuel utilization: detailed kinetic combustion...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Improving alternative fuel utilization: detailed kinetic combustion modeling & experimental testing Improving alternative fuel utilization: detailed kinetic combustion modeling &...

246

Laser-matter interaction at intensities of 10 sup 12 W/cm sup 2 and below  

SciTech Connect (OSTI)

For single pulsed laser-matter interactions at sufficiently high intensity, the electron density in the ablated vapor is large enough to absorb the laser radiation before it can reach the dense target material. The resulting interaction can be described in terms of energy flows: laser energy is absorbed in the plasma in front of the target and reappears as thermal electron energy and secondary radiation, part of which impinges upon and heats the dense target material at the dense material-vapor interface. This heating in turn drives ablation, thereby providing a self-consistent mass source for the laser absorption, energy conversion, and transmission. Under typical conditions of laser intensity, pulse width and spot size, the flow patterns can be strongly two-dimensional. We have modified the inertial confinement fusion code LASNEX to simulate gaseous and some dense material aspects for the relatively low intensity, long-pulse-length conditions to interest in many laser-related applications. The unique aspect to our treatment consists of an ablation model which defines a dense material vapor interface and then calculates the mass flow across this interface. The model, at present, treats the dense material as a rigid, two-dimensional simulational mass and heat reservoir, suppressing all hydrodynamical motion in the dense material. The modeling is being developed and refined through simulation of experiments, as well as through the investigation of internal inconsistencies, and some simulations of model problems. 5 refs., 14 figs., 1 tab.

Goldman, S.R.; Dingus, R.S.; Kirkpatrick, R.C.; Kopp, R.A.; Stover, E.K.; Watt, R.G.

1990-01-01T23:59:59.000Z

247

Low power cw-laser signatures on human skin  

SciTech Connect (OSTI)

Impact of cw laser radiation on autofluorescence features of human skin is studied. Two methods of autofluorescence detection are applied: the spectral method with the use of a fibreoptic probe and spectrometer for determining the autofluorescence recovery kinetics at a fixed skin area of {approx}12 mm{sup 2}, and the multispectral visualisation method with the use of a multispectral imaging camera for visualising long-term autofluorescence changes in a skin area of {approx}4 cm{sup 2}. The autofluorescence recovery kinetics after preliminary laser irradiation is determined. Skin autofluorescence images with visible long-term changes - 'signatures' of low power laser treatment are acquired. (application of lasers and laser-optical methods in life sciences)

Lihachev, A; Lesinsh, J; Jakovels, D; Spigulis, J [Institute of Atomic Physics and Spectroscopy, University of Latvia, Riga (Latvia)

2011-01-24T23:59:59.000Z

248

Laser device  

DOE Patents [OSTI]

A laser device includes a virtual source configured to aim laser energy that originates from a true source. The virtual source has a vertical rotational axis during vertical motion of the virtual source and the vertical axis passes through an exit point from which the laser energy emanates independent of virtual source position. The emanating laser energy is collinear with an orientation line. The laser device includes a virtual source manipulation mechanism that positions the virtual source. The manipulation mechanism has a center of lateral pivot approximately coincident with a lateral index and a center of vertical pivot approximately coincident with a vertical index. The vertical index and lateral index intersect at an index origin. The virtual source and manipulation mechanism auto align the orientation line through the index origin during virtual source motion.

Scott, Jill R. (Idaho Falls, ID); Tremblay, Paul L. (Idaho Falls, ID)

2008-08-19T23:59:59.000Z

249

Palliative Treatment of Rectal Carcinoma Recurrence Using Radiofrequency Ablation  

SciTech Connect (OSTI)

Purpose: To evaluate the safety and efficacy of CT-guided radiofrequency (RF) ablation for the palliative treatment of recurrent unresectable rectal tumors. Materials and Methods: Twenty-seven patients with locally recurrent rectal cancer were treated with computed tomography (CT)-guided RF ablation. Therapy was performed with the patient under conscious sedation with a seven- or a nine-array expandable RF electrode for 8-10 min at 80-110 Degree-Sign C and a power of 90-110 W. All patients went home under instructions the next day of the procedure. Brief Pain Inventory score was calculated before and after (1 day, 1 week, 1 month, 3 months, and 6 months) treatment. Results: Complete tumor necrosis rate was 77.8% (21 of a total 27 procedures) despite lesion location. BPI score was dramatically decreased after the procedure. The mean preprocedure BPI score was 6.59, which decreased to 3.15, 1.15, and 0.11 at postprocedure day 1, week 1, and month 1, respectively, after the procedure. This decrease was significant (p < 0.01 for the first day and p < 0.001 for the rest of the follow-up intervals (paired Student t test; n - 1 = 26) for all periods during follow-up. Six patients had partial tumor necrosis, and we were attempted to them with a second procedure. Although the necrosis area showed a radiographic increase, no complete necrosis was achieved (secondary success rate 65.6%). No immediate or delayed complications were observed. Conclusion: CT-guided RF ablation is a minimally invasive, safe, and highly effective technique for treatment of malignant rectal recurrence. The method is well tolerated by patients, and pain relief is quickly achieved.

Mylona, Sophia, E-mail: mylonasophia@yahoo.com; Karagiannis, Georgios, E-mail: gekaragiannis@yahoo.gr; Patsoura, Sofia, E-mail: sofia.patsoura@yahoo.gr [Hellenic Red Cross Hospital 'Korgialenio-Benakio' (Greece); Galani, Panagiota, E-mail: gioulagalani@yahoo.com [Amalia Fleming Hospital (Greece); Pomoni, Maria, E-mail: marypomoni@gmail.com [Evgenidion Hospital (Greece); Thanos, Loukas, E-mail: loutharad@yahoo.com [Sotiria Hospital (Greece)

2012-08-15T23:59:59.000Z

250

Use of Semiflexible Applicators for Radiofrequency Ablation of Liver Tumors  

SciTech Connect (OSTI)

Purpose. To evaluate the feasibility and potential advantages of the radiofrequency ablation of liver tumors using new MRI-compatible semiflexible applicators in a closed-bore high-field MRI scanner. Methods. We treated 8 patients with 12 malignant liver tumors of different origin (5 colorectal carcinoma, 2 cholangiocellular carcinoma, 1 breast cancer) under MRI guidance. Radiofrequency ablation (RFA) was performed using 5 cm Rita Starburst Semi-Flex applicators (Rita Medical Systems, Milwaukee, WI, USA) which are suitable for MR- and CT-guided interventions and a 150 W RF generator. All interventions were performed in a closed-bore 1.5 T high-field MRI scanner for MRI-guided RFA using fast T1-weighted gradient echo sequences and T2-weighted ultra-turbo spin echo sequences. Control and follow-up MRI examinations were performed on the next day, at 6 weeks, and every 3 months after RFA. Control MRI were performed as double-contrast MRI examinations (enhancement with iron oxide and gadopentetate dimeglumine). All interventions were performed with the patient under local anesthesia and analgo-sedation. Results. The mean diameter of the treated hepatic tumors was 2.4 cm ({+-}0.6 cm, range 1.0-3.2 cm). The mean diameter of induced necrosis was 3.1 cm ({+-}0.4 cm). We achieved complete ablation in all patients. Follow-up examinations over a duration of 7 months ({+-}1.3 months, range 4-9 month) showed a local control rate of 100% in this group of patients. All interventions were performed without major complications; only 2 subcapsular hematomas were documented. Conclusion. RFA of liver tumors using semiflexible applicators in closed-bore 1.5 T scanner systems is feasible. These applicators might simplify the RFA of liver tumors under MRI control. The stiff distal part of the applicator facilitates its repositioning.

Gaffke, G., E-mail: gunnar.gaffke@charite.de; Gebauer, B.; Knollmann, F.D. [Universitaetsmedizin Berlin, Klinik fuer Strahlenheilkunde und Poliklinik, Charite (Germany); Helmberger, T. [Universitaet Muenchen, Institut fuer klinische Radiologie Grosshadern (Germany); Ricke, J. [Universitaetsmedizin Berlin, Klinik fuer Strahlenheilkunde und Poliklinik, Charite (Germany); Oettle, H. [Universitaetsmedizin Berlin, Campus-Virchow-Klinikum, Medizinische Klinik mit Schwerpunkt Haematologie und Onkologie der Charite (Germany); Felix, R.; Stroszczynski, C. [Universitaetsmedizin Berlin, Klinik fuer Strahlenheilkunde und Poliklinik, Charite (Germany)

2006-04-15T23:59:59.000Z

251

EJECTA KNOT FLICKERING, MASS ABLATION, AND FRAGMENTATION IN CASSIOPEIA A  

SciTech Connect (OSTI)

Ejecta knot flickering, ablation tails, and fragmentation are expected signatures associated with the gradual dissolution of high-velocity supernova (SN) ejecta caused by their passage through an inhomogeneous circumstellar medium or interstellar medium (ISM). Such phenomena mark the initial stages of the gradual merger of SN ejecta with and the enrichment of the surrounding ISM. Here we report on an investigation of this process through changes in the optical flux and morphology of several high-velocity ejecta knots located in the outskirts of the young core-collapse SN remnant Cassiopeia A using Hubble Space Telescope images. Examination of WFPC2 F675W and combined ACS F625W + F775W images taken between 1999 June and 2004 December of several dozen debris fragments in the remnant's northeast ejecta stream and along the remnant's eastern limb reveal substantial emission variations ('flickering') over timescales as short as nine months. Such widespread and rapid variability indicates knot scale lengths {approx_equal} 10{sup 15} cm and a highly inhomogeneous surrounding medium. We also identify a small percentage of ejecta knots located all around the remnant's outer periphery which show trailing emissions typically 0.''2-0.''7 in length aligned along the knot's direction of motion suggestive of knot ablation tails. We discuss the nature of these trailing emissions as they pertain to ablation cooling, knot disruption, and fragmentation, and draw comparisons to the emission 'strings' seen in {eta} Car. Finally, we identify several tight clusters of small ejecta knots which resemble models of shock-induced fragmentation of larger SN ejecta knots caused by a high-velocity interaction with a lower density ambient medium.

Fesen, Robert A.; Zastrow, Jordan A.; Hammell, Molly C. [6127 Wilder Laboratory, Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Shull, J. Michael; Silvia, Devin W. [CASA, Department of Astrophysical and Planetary Science, University of Colorado, Boulder, CO 80309 (United States)

2011-08-01T23:59:59.000Z

252

Chemical kinetics modeling  

SciTech Connect (OSTI)

This project emphasizes numerical modeling of chemical kinetics of combustion, including applications in both practical combustion systems and in controlled laboratory experiments. Elementary reaction rate parameters are combined into mechanisms which then describe the overall reaction of the fuels being studied. Detailed sensitivity analyses are used to identify those reaction rates and product species distributions to which the results are most sensitive and therefore warrant the greatest attention from other experimental and theoretical research programs. Experimental data from a variety of environments are combined together to validate the reaction mechanisms, including results from laminar flames, shock tubes, flow systems, detonations, and even internal combustion engines.

Westbrook, C.K.; Pitz, W.J. [Lawrence Livermore National Laboratory, CA (United States)

1993-12-01T23:59:59.000Z

253

Imaging of lithium pellet ablation trails and measurement of g profiles in TFTR  

E-Print Network [OSTI]

Imaging of lithium pellet ablation trails and measurement of g profiles in TFTR J. L. Terry, E. S March 1992) Video images with 2 ps exposures of the Li+ emission in Li pellet ablation clouds have been obtained in a variety of Tokamak Fusion Test Reactor tokamak discharges. The pellet clouds are viewed from

Garnier, Darren T.

254

Snow ablation modelling in a mature aspen stand of the boreal forest  

E-Print Network [OSTI]

of components of energy transfer at the forest ¯oor. Our previous work successfully predicted snow ablationSnow ablation modelling in a mature aspen stand of the boreal forest J. P. Hardy,1* R. E. Davis,1 R below forest canopies. This work represents a second test of our basic modelling scenario by predict

Ni-Meister, Wenge

255

High temperature ablation resistance of ZrNp reinforced W matrix composites  

E-Print Network [OSTI]

modulus of elasticity, good thermal shock resistance, stiffness and good high temperature strengthHigh temperature ablation resistance of ZrNp reinforced W matrix composites Malik Adeel Umer microscopy (SEM) For the purpose of improving the high temperature ablation resistance of tungsten

Hong, Soon Hyung

256

Elevated temperature ablation resistance of HfC particle-reinforced tungsten composites  

E-Print Network [OSTI]

C­W was attributed to the low thermal conductivity, high oxidation resistance, and high melting point of the Hf melting points (e.g., 3440 °C for W), high moduli of elasticity, good thermal shock resistances, and good torch was used to ablate the samples at high temperature. Ablation resistance improved with an in

Hong, Soon Hyung

257

IDetachable, Human-Rated, Ablative Environmentally Compliant TPSLunar Surface Systems 2008 Phase II  

E-Print Network [OSTI]

Systems 2008 Phase II Proposal X8.01-8631 Lightweight Hybrid Ablator Incorporating Aerogel-Filled Open skeleton filled with a high temperature nanoscale aerogel insulator. Structural integrity and high insulation behavior have been demonstrated when used in combination with a non-ablating, coated carbon

258

Ambient gas effects on the dynamics of laser-produced tin plume expansion  

E-Print Network [OSTI]

mitigation in a laser-produced tin plasma is one of the mostambient pressure, the tin species with kinetic Downloaded 19Sn + species ejected by the tin plume exhibits a Downloaded

Harilal, S S; O'Shay, B; Tillac, M S; Tao, Y

2006-01-01T23:59:59.000Z

259

Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel beams  

SciTech Connect (OSTI)

We report the fabrication of micro and nano-disks in single layer chemical vapor deposition graphene on glass substrate using femtosecond laser ablation with vortex Bessel beams. The fabricated graphene disks with diameters ranging from 650?nm to 4??m were characterized by spatially resolved micro-Raman spectroscopy. The variation of ablation threshold was investigated as a function of the number of pulses showing an incubation effect. A very high degree of size control of the fabricated graphene disks is enabled using a sequence of femtosecond pulses with different vortex orders.

Wetzel, Benjamin, E-mail: benjamin.wetzel@femto-st.fr; Xie, Chen; Lacourt, Pierre-Ambroise; Dudley, John M.; Courvoisier, Francois [Département d'Optique P.M. Duffieux, Institut FEMTO-ST, UMR–6174 CNRS, Université de Franche-Comté, 25030 Besançon (France)] [Département d'Optique P.M. Duffieux, Institut FEMTO-ST, UMR–6174 CNRS, Université de Franche-Comté, 25030 Besançon (France)

2013-12-09T23:59:59.000Z

260

Laser goniometer  

DOE Patents [OSTI]

The laser goniometer is an apparatus which permits an operator to sight along a geologic feature and orient a collimated lamer beam to match the attitude of the feature directly. The horizontal orientation (strike) and the angle from horizontal (dip), are detected by rotary incremental encoders attached to the laser goniometer which provide a digital readout of the azimuth and tilt of the collimated laser beam. A microprocessor then translates the square wave signal encoder outputs into an ASCII signal for use by data recording equipment.

Fairer, George M. (Boulder, CO); Boernge, James M. (Lakewood, CO); Harris, David W. (Lakewood, CO); Campbell, DeWayne A. (Littleton, CO); Tuttle, Gene E. (Littleton, CO); McKeown, Mark H. (Golden, CO); Beason, Steven C. (Lakewood, CO)

1993-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Task 12: Laser cleaning of contaminated painted surfaces. Semi-annual report, April 1, 1996--September 30, 1996  

SciTech Connect (OSTI)

Paint contaminated with radionuclides and other hazardous materials is common in Department of Energy (DOE) facilities. Facility decommissioning and decontamination requires the removal of contaminated paint. Paint removal technologies include laser- and abrasive-based systems. F2 Associates are utilizing a pulsed-repetition CO{sub 2} laser that produces a 2.5-cm x 2.5-cm beam which can be scanned across a 30- x 100-cm raster and, when placed on a robot, can be designed to clean any surface that the robot can be programmed to follow. Causing little or no damage to the substrate (concrete, steel, etc.), the laser ablates the material to be removed from a given surface. Ablated material is then pulled into a filtration and collection (VAC-PAC) system to prevent the hazardous substances from entering into the atmosphere. The VAC-PAC system deposits the ablated material into waste drums which may be removed from the system without compromising the integrity of the seal, allowing a new drum to be set up for collection without leakage of the ablated material into the atmosphere.

Grisanti, A.A.; Hassett, D.J.

1997-05-01T23:59:59.000Z

262

Interpretation of time-of-flight distributions for neutral particles under pulsed laser evaporation using direct Monte Carlo simulation  

SciTech Connect (OSTI)

A theoretical study of the time-of-flight (TOF) distributions under pulsed laser evaporation in vacuum has been performed. A database of TOF distributions has been calculated by the direct simulation Monte Carlo (DSMC) method. It is shown that describing experimental TOF signals through the use of the calculated TOF database combined with a simple analysis of evaporation allows determining the irradiated surface temperature and the rate of evaporation. Analysis of experimental TOF distributions under laser ablation of niobium, copper, and graphite has been performed, with the evaluated surface temperature being well agreed with results of the thermal model calculations. General empirical dependences are proposed, which allow indentifying the regime of the laser induced thermal ablation from the TOF distributions for neutral particles without invoking the DSMC-calculated database.

Morozov, Alexey A., E-mail: morozov@itp.nsc.ru [Institute of Thermophysics SB RAS, 1 Lavrentyev Ave., 630090 Novosibirsk (Russian Federation)

2013-12-21T23:59:59.000Z

263

Method for materials deposition by ablation transfer processing  

DOE Patents [OSTI]

A method in which a thin layer of semiconducting, insulating, or metallic material is transferred by ablation from a source substrate, coated uniformly with a thin layer of said material, to a target substrate, where said material is desired, with a pulsed, high intensity, patternable beam of energy. The use of a patternable beam allows area-selective ablation from the source substrate resulting in additive deposition of the material onto the target substrate which may require a very low percentage of the area to be covered. Since material is placed only where it is required, material waste can be minimized by reusing the source substrate for depositions on multiple target substrates. Due to the use of a pulsed, high intensity energy source the target substrate remains at low temperature during the process, and thus low-temperature, low cost transparent glass or plastic can be used as the target substrate. The method can be carried out atmospheric pressures and at room temperatures, thus eliminating vacuum systems normally required in materials deposition processes. This invention has particular application in the flat panel display industry, as well as minimizing materials waste and associated costs.

Weiner, Kurt H. (San Jose, CA)

1996-01-01T23:59:59.000Z

264

LASER ACCELERATORS  

E-Print Network [OSTI]

UNIVERSITY OF CALIFORNIA Accelerator & Fusion Researchat the 1983 Particle Accelerator Conference, Santa Fe, NM,March 21-23, 1983 LASER ACCELERATORS A.M. Sessler TWO-WEEK

Sessler, A.M.

2008-01-01T23:59:59.000Z

265

Laser barometer  

SciTech Connect (OSTI)

This paper describes an invention of a pressure measuring instrument which uses laser radiation to sense the pressure in an enclosed environment by means of measuring the change in refractive index of a gas - which is pressure dependent.

Abercrombie, K.R.; Shiels, D.; Rash, T.

1998-04-01T23:59:59.000Z

266

Laser Optomechanics  

E-Print Network [OSTI]

Cavity optomechanics explores the coupling between the optical field and the mechanical oscillation to induce cooling and regenerative oscillation in a mechanical oscillator. So far, optomechanics relies on the detuning between the cavity and an external pump laser, where the laser acts only as a power supply. Here, we report a new scheme with mutual coupling between a mechanical oscillator that supports a mirror of a vertical-cavity surface-emitting laser (VCSEL) and the optical field, greatly enhancing the light-matter energy transfer. In this work, we used an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror in a VCSEL, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity with > 550 nm self-oscillation amplitude of the micro-mechanical oscillator, two to three orders of magnitude larger than typical. This new scheme not only offers an efficient approach for high-...

Yang, Weijian; Ng, Kar Wei; Rao, Yi; Chase, Christopher; Chang-Hasnain, Connie J

2015-01-01T23:59:59.000Z

267

Glass particles produced by laser ablation for ICP-MS measurements  

E-Print Network [OSTI]

NIST) and X-ray fluorescence (XRF) monitor samples from Glenstandards), and figure 2 (XRF standards). The error barsand 160 and 180 nm for XRF monitor samples. These data show

Gonzalez, J.; Liu, C.; Wen, S.; Mao, X.; Russo, R.E.

2008-01-01T23:59:59.000Z

268

Spatio-temporal mapping of ablated species in ultrafast laser-produced graphite plasmas  

E-Print Network [OSTI]

cannot leave their lattice positions before pulse termination. This very large deposited intensity can, diamond-like carbon, carbon nanotubes and nanowires) have become a focus for numerous studies because of these carbon species. In this context, it was reported that carbon dimers have an essential role

Harilal, S. S.

269

Morphology of Femtosecond Laser Ablated Borosilicate Glass Surfaces Adela Ben-Yakar and Robert L. Byer  

E-Print Network [OSTI]

carried out experiments on borosilicate glass (1.1 mm thick, Precision Glass and Optics, Ltd.), also known very weak etchant) for about 20 minutes. We irradiated the glass samples with near-infrared (780-800 nm = 0.12 J/mm2 . incident beam. Following irradiation, the samples were analyzed with a scanning

Harkin, Anthony

270

Microscopic mechanisms of laser ablation of organic solids in the thermal and stress confinement irradiation regimes  

E-Print Network [OSTI]

irradiation is defined by the combination of the optical, mechanical and thermodynamic properties irradiation regimes Leonid V. Zhigileia) and Barbara J. Garrisonb) Department of Chemistry, The Pennsylvania confinement regime results in broader velocity distributions in the direction normal to the irradiated surface

Zhigilei, Leonid V.

271

Laser Ablation Synthesis and Electron Transport Studies of Tin Oxide Nanowires**  

E-Print Network [OSTI]

and solar cells.[7±9] In addition, SnO2 thin films have been extensively studied and used as chemical demonstrated to work as sensitive UV and polarized UV detectors. A quartz tube furnace was used for our SnO2 of the furnace, and Si±SiO2 sub- strates covered with 20 nm gold catalytic clusters were placed in the middle

Zhou, Chongwu

272

PROOF COPY 019605JAP Effect of pulsing parameters on laser ablative cleaning of copper oxides  

E-Print Network [OSTI]

of copper oxides Jie Zhang,a Youneng Wang, Peng Cheng, and Y. Lawrence Yao Department of Mechanical; accepted 23 January 2006 The characteristics of copper oxide removal are comparably investigated under. Experiments are carried out on copper samples having different oxide layer thicknesses. The copper oxide layer

Yao, Y. Lawrence

273

Improvements to Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun withconfinementEtching.348 270 300 219 255RetrievalsVehiclesLaboratoryfor

274

Polymer Stable Magnesium Nanocomposites Prepared by Laser Ablation for Efficient Hydrogen Storage  

E-Print Network [OSTI]

Hydrogen is a promising alternative energy carrier that can potentially facilitate the transition from fossil fuels to sources of clean energy because of its prominent advantages such as high energy density (142 MJ per kg), great variety of potential sources (for example water, biomass, organic matter), and low environmental impact (water is the sole combustion product). However, due to its light weight, the efficient storage of hydrogen is still an issue investigated intensely. Various solid media have been considered in that respect among which magnesium hydride stands out as a candidate offering distinct advantages. Recent theoretical work indicates that MgH2 becomes less thermodynamically stable as particle diameter decreases below 2 nm. Our DFT (density functional theory) modeling studies have shown that the smallest enthalpy change, corresponding to 2 unit-cell thickness (1.6 {\\AA} Mg/3.0{\\AA} MgH2) of the film, is 57.7 kJ/molMg. This enthalpy change is over 10 kJ per molMg smaller than that of the bulk...

Makridis, S S; Panagakos, G; Kikkinides, E S; Stubos, A K; Wagener, P; Barcikowski, S

2013-01-01T23:59:59.000Z

275

Ultrafast electron beam imaging of femtosecond laser-induced plasma Junjie Li, Xuan Wang, Zhaoyang Chen, Richard Clinite, Samuel S. Mao et al.  

E-Print Network [OSTI]

, Beijing 100190, China and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China in the early stage of laser ablation of a copper target are investigated in real time by making ultrafast have been a subject of intensive investigation in recent years ow- ing to its importance in a wide

Cao, Jianming

276

Elemental and isotopic analysis of inorganic salts by laser desorption ionization mass spectrometry  

SciTech Connect (OSTI)

Laser desorption ionization mass spectrometry is applied for the analysis of elements as well as their isotopic composition in different inorganic salts. At very low laser energies the inorganic ions are desorbed and ionized from the thin layer of the sample surface. The naturally occurring isotopes of alkali and silver ions are resolved using time of flight mass spectrometer. Further increase in laser energy shows the appearance of Al, Cr, and Fe ions in the mass spectra. This indicates the penetration laser beam beyond the sample surface leading to the ablation of sample target at higher energies. The simultaneous appearance of atomic ions from the sample target at relatively higher laser energies hampers the unambiguous identification of amino acid residues from the biomolecular ions in MALDI-MS.

Jayasekharan, T.; Sahoo, N. K. [Applied Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2013-02-05T23:59:59.000Z

277

Laser EYE SURGERY LASIK and Excimer Lasers  

E-Print Network [OSTI]

Laser EYE SURGERY LASIK and Excimer Lasers Michael Hutchins #12;The PROBLEM opia - near sightedness - Laser Assisted in SItu Keratomileusis atomileusis is the procedure of opening the eye and ring the cornea. SIK uses an excimer laser to perform the alterations an er a knife or a femtosecond laser

Fygenson, Deborah Kuchnir

278

Oxygen-assisted multipass cutting of carbon fiber reinforced plastics with ultra-short laser pulses  

SciTech Connect (OSTI)

Deep multipass cutting of bidirectional and unidirectional carbon fiber reinforced plastics (CFRP) with picosecond laser pulses was investigated in different static atmospheres as well as with the assistance of an oxygen or nitrogen gas flow. The ablation rate was determined as a function of the kerf depth and the resulting heat affected zone was measured. An assisting oxygen gas flow is found to significantly increase the cutting productivity, but only in deep kerfs where the diminished evaporative ablation due to the reduced laser fluence reaching the bottom of the kerf does not dominate the contribution of reactive etching anymore. Oxygen-supported cutting was shown to also solve the problem that occurs when cutting the CFRP parallel to the fiber orientation where a strong deformation and widening of the kerf, which temporarily slows down the process speed, is revealed to be typical for processing in standard air atmospheres.

Kononenko, T. V.; Komlenok, M. S.; Konov, V. I. [Natural Sciences Center, General Physics Institute, Vavilov str. 38, 119991 Moscow (Russian Federation); National Research Nuclear University, “MEPhI,” Kashirskoye shosse 31, 115409 Moscow (Russian Federation); Freitag, C. [Universität Stuttgart, Institut für Strahlwerkzeuge (IFSW), Pfaffenwaldring 43, 70569 Stuttgart (Germany); GSaME Graduate School of Excellence Advanced Manufacturing Engineering, Nobelstrasse 12, 70569 Stuttgart (Germany); Onuseit, V.; Weber, R.; Graf, T. [Universität Stuttgart, Institut für Strahlwerkzeuge (IFSW), Pfaffenwaldring 43, 70569 Stuttgart (Germany)

2014-03-14T23:59:59.000Z

279

Process for ion-assisted laser deposition of biaxially textured layer on substrate  

DOE Patents [OSTI]

A process for depositing a biaxially aligned intermediate layer over a non-single crystal substrate is disclosed which permits the subsequent deposition thereon of a biaxially oriented superconducting film. The process comprises depositing on a substrate by laser ablation a material capable of being biaxially oriented and also capable of inhibiting the migration of substrate materials through the intermediate layer into such a superconducting film, while simultaneously bombarding the substrate with an ion beam. In a preferred embodiment, the deposition is carried out in the same chamber used to subsequently deposit a superconducting film over the intermediate layer. In a further aspect of the invention, the deposition of the superconducting layer over the biaxially oriented intermediate layer is also carried out by laser ablation with optional additional bombardment of the coated substrate with an ion beam during the deposition of the superconducting film.

Russo, Richard E. (Walnut Creek, CA); Reade, Ronald P. (Berkeley, CA); Garrison, Stephen M. (Palo Alto, CA); Berdahl, Paul (Oakland, CA)

1995-01-01T23:59:59.000Z

280

Along the Laser Beampath  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

8 20 | Next | Last Back to Index NIF Laser Bay Each NIF laser bay is 122 meters (400 feet) long and contains 96 beamlines. This side view of Laser Bay 2 shows the four-high laser...

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Laser Safety Introduction  

E-Print Network [OSTI]

Laser Safety #12;Introduction · A Laser is a device that controls the way energized atoms release photons. · LASER is an acronym for "Light Amplification by Stimulated Emission of Radiation" · The light emitted by a laser is non

McQuade, D. Tyler

282

Percutaneous Irreversible Electroporation Lung Ablation: Preliminary Results in a Porcine Model  

SciTech Connect (OSTI)

Objective: Irreversible electroporation (IRE) uses direct electrical pulses to create permanent 'pores' in cell membranes to cause cell death. In contrast to conventional modalities, IRE has a nonthermal mechanism of action. Our objective was to study the histopathological and imaging features of IRE in normal swine lung. Materials and Methods: Eleven female swine were studied for hyperacute (8 h), acute (24 h), subacute (96 h), and chronic (3 week) effects of IRE ablation in lung. Paired unipolar IRE applicators were placed under computed tomography (CT) guidance. Some applicators were deliberately positioned near bronchovascular structures. IRE pulse delivery was synchronized with the cardiac rhythm only when ablation was performed within 2 cm of the heart. Contrast-enhanced CT scan was performed immediately before and after IRE and at 1 and 3 weeks after IRE ablation. Representative tissue was stained with hematoxylin and eosin for histopathology. Results: Twenty-five ablations were created: ten hyperacute, four acute, and three subacute ablations showed alveolar edema and necrosis with necrosis of bronchial, bronchiolar, and vascular epithelium. Bronchovascular architecture was maintained. Chronic ablations showed bronchiolitis obliterans and alveolar interstitial fibrosis. Immediate post-procedure CT images showed linear or patchy density along the applicator tract. At 1 week, there was consolidation that resolved partially or completely by 3 weeks. Pneumothorax requiring chest tube developed in two animals; no significant cardiac arrhythmias were noted. Conclusion: Our preliminary porcine study demonstrates the nonthermal and extracellular matrix sparing mechanism of action of IRE. IRE is a potential alternative to thermal ablative modalities.

Deodhar, Ajita [Memorial Sloan Kettering Cancer Center, Interventional Radiology and Image-Guided Therapies (United States); Monette, Sebastien [Memorial Sloan Kettering Cancer Center, Laboratory of Comparative Pathology (United States); Single, Gordon W.; Hamilton, William C. [Angiodynamics, Inc (United States); Thornton, Raymond H.; Sofocleous, Constantinos T.; Maybody, Majid; Solomon, Stephen B., E-mail: solomons@mskcc.org [Memorial Sloan Kettering Cancer Center, Interventional Radiology and Image-Guided Therapies (United States)

2011-12-15T23:59:59.000Z

283

Survival after Radiofrequency Ablation in 122 Patients with Inoperable Colorectal Lung Metastases  

SciTech Connect (OSTI)

Purpose. To analyze the factors associated with favorable survival in patients with inoperable colorectal lung metastases treated with percutaneous image-guided radiofrequency ablation. Methods. Between 2002 and 2011, a total of 398 metastases were ablated in 122 patients (87 male, median age 68 years, range 29-90 years) at 256 procedures. Percutaneous CT-guided cool-tip radiofrequency ablation was performed under sedation/general anesthesia. Maximum tumor size, number of tumors ablated, number of procedures, concurrent/prior liver ablation, previous liver or lung resection, systemic chemotherapy, disease-free interval from primary resection to lung metastasis, and survival from first ablation were recorded prospectively. Kaplan-Meier analysis was performed, and factors were compared by log rank test. Results. The initial number of metastases ablated was 2.3 (range 1-8); the total number was 3.3 (range 1-15). The maximum tumor diameter was 1.7 (range 0.5-4) cm, and the number of procedures was 2 (range 1-10). The major complication rate was 3.9 %. Overall median and 3-year survival rate were 41 months and 57 %. Survival was better in patients with smaller tumors-a median of 51 months, with 3-year survival of 64 % for tumors 2 cm or smaller versus 31 months and 44 % for tumors 2.1-4 cm (p = 0.08). The number of metastases ablated and whether the tumors were unilateral or bilateral did not affect survival. The presence of treated liver metastases, systemic chemotherapy, or prior lung resection did not affect survival. Conclusion. Three-year survival of 57 % in patients with inoperable colorectal lung metastases is better than would be expected with chemotherapy alone. Patients with inoperable but small-volume colorectal lung metastases should be referred for ablation.

Gillams, Alice, E-mail: alliesorting@gmail.com [The London Clinic, Radiology Department (United Kingdom); Khan, Zahid [Countess of Chester Hospital (United Kingdom); Osborn, Peter [Queen Alexandra Hospital (United Kingdom); Lees, William [University College London Medical School (United Kingdom)

2013-06-15T23:59:59.000Z

284

Multidimensional simulation and chemical kinetics development...  

Broader source: Energy.gov (indexed) [DOE]

processes. deer09aceves.pdf More Documents & Publications Chemical Kinetic Research on HCCI & Diesel Fuels Chemical Kinetic Research on HCCI & Diesel Fuels Simulation of High...

285

Laser Cosmology  

E-Print Network [OSTI]

Recent years have seen tremendous progress in our understanding of the cosmos, which in turn points to even deeper questions to be further addressed. Concurrently the laser technology has undergone dramatic revolutions, providing exciting opportunity for science applications. History has shown that the symbiosis between direct observations and laboratory investigation is instrumental in the progress of astrophysics. We believe that this remains true in cosmology. Current frontier phenomena related to particle astrophysics and cosmology typically involve one or more of the following conditions: (1) extremely high energy events; (2) very high density, high temperature processes; (3) super strong field environments. Laboratory experiments using high intensity lasers can calibrate astrophysical observations, investigate underlying dynamics of astrophysical phenomena, and probe fundamental physics in extreme limits. In this article we give an overview of the exciting prospect of laser cosmology. In particular, we showcase its unique capability of investigating frontier cosmology issues such as cosmic accelerator and quantum gravity.

Pisin Chen

2014-02-24T23:59:59.000Z

286

Outcome after Radiofrequency Ablation of Sarcoma Lung Metastases  

SciTech Connect (OSTI)

PurposeResection is the mainstay of management in patients with sarcoma lung metastases, but there is a limit to how many resections can be performed. Some patients with inoperable disease have small-volume lung metastases that are amenable to thermal ablation. We report our results after radiofrequency ablation (RFA).MethodsThis is a retrospective study of patients treated from 2007 to 2012 in whom the intention was to treat all sites of disease and who had a minimum CT follow-up of 4 months. Treatment was performed under general anesthesia/conscious sedation using cool-tip RFA. Follow-up CT scans were analyzed for local control. Primary tumor type, location, grade, disease-free interval, prior resection/chemotherapy, number and size of lung tumors, uni- or bilateral disease, complications, and overall and progression-free survival were recorded.ResultsTwenty-two patients [15 women; median age 48 (range 10–78) years] with 55 lung metastases were treated in 30 sessions. Mean and median tumor size and initial number were 0.9 cm and 0.7 (range 0.5–2) cm, and 2.5 and 1 (1–7) respectively. Median CT and clinical follow-up were 12 (4–54) and 20 (8–63) months, respectively. Primary local control rate was 52 of 55 (95 %). There were 2 of 30 (6.6 %) Common Terminology Criteria grade 3 complications with no long-term sequelae. Mean (median not reached) and 2- and 3-year overall survival were 51 months, and 94 and 85 %. Median and 1- and 2-year progression-free survival were 12 months, and 53 and 23 %. Prior disease-free interval was the only significant factor to affect overall survival.ConclusionRFA is a safe and effective treatment for patients with small-volume sarcoma metastases.

Koelblinger, Claus, E-mail: claus.koelblinger@bhs.at [KH Barmherzige Schwestern Ried, Department of Radiology (Austria); Strauss, Sandra, E-mail: s.strauss@ucl.ac.uk [UCL and UCLH, Department of Medical Oncology (United Kingdom); Gillams, Alice, E-mail: alliesorting@gmail.com [The London Clinic, Department of Radiology (United Kingdom)

2013-05-14T23:59:59.000Z

287

Laser barometer  

DOE Patents [OSTI]

A pressure measuring instrument that utilizes the change of the refractive index of a gas as a function of pressure and the coherent nature of a laser light to determine the barometric pressure within an environment. As the gas pressure in a closed environment varies, the index of refraction of the gas changes. The amount of change is a function of the gas pressure. By illuminating the gas with a laser light source, causing the wavelength of the light to change, pressure can be quantified by measuring the shift in fringes (alternating light and dark bands produced when coherent light is mixed) in an interferometer.

Abercrombie, Kevin R. (Westminster, CO); Shiels, David (Thornton, CO); Rash, Tim (Aurora, CO)

2001-02-06T23:59:59.000Z

288

Reciprocal Relations Between Kinetic Curves  

E-Print Network [OSTI]

We study coupled irreversible processes. For linear or linearized kinetics with microreversibility, $\\dot{x}=Kx$, the kinetic operator $K$ is symmetric in the entropic inner product. This form of Onsager's reciprocal relations implies that the shift in time, $\\exp (Kt)$, is also a symmetric operator. This generates reciprocity relations between kinetic curves. For example, for the Master equation, if we start the process from the $i$th pure state and measure the probability $p_j(t)$ of the $j$th state ($j\

Yablonsky, G S; Constales, D; Galvita, V; Marin, G B

2010-01-01T23:59:59.000Z

289

Chemical Looping Combustion Kinetics  

SciTech Connect (OSTI)

One of the most promising methods of capturing CO{sub 2} emitted by coal-fired power plants for subsequent sequestration is chemical looping combustion (CLC). A powdered metal oxide such as NiO transfers oxygen directly to a fuel in a fuel reactor at high temperatures with no air present. Heat, water, and CO{sub 2} are released, and after H{sub 2}O condensation the CO{sub 2} (undiluted by N{sub 2}) is ready for sequestration, whereas the nickel metal is ready for reoxidation in the air reactor. In principle, these processes can be repeated endlessly with the original nickel metal/nickel oxide participating in a loop that admits fuel and rejects ash, heat, and water. Our project accumulated kinetic rate data at high temperatures and elevated pressures for the metal oxide reduction step and for the metal reoxidation step. These data will be used in computational modeling of CLC on the laboratory scale and presumably later on the plant scale. The oxygen carrier on which the research at Utah is focused is CuO/Cu{sub 2}O rather than nickel oxide because the copper system lends itself to use with solid fuels in an alternative to CLC called 'chemical looping with oxygen uncoupling' (CLOU).

Edward Eyring; Gabor Konya

2009-03-31T23:59:59.000Z

290

Systems and methods for laser assisted sample transfer to solution for chemical analysis  

SciTech Connect (OSTI)

Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

Van Berkel, Gary J.; Kertesz, Vilmos; Ovchinnikova, Olga S.

2014-06-03T23:59:59.000Z

291

Systems and methods for laser assisted sample transfer to solution for chemical analysis  

DOE Patents [OSTI]

Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

Van Berkel, Gary J; Kertesz, Vilmos; Ovchinnikova, Olga S

2013-08-27T23:59:59.000Z

292

Kinetics and mechanisms of reactions involving small aromatic reactive intermediates  

SciTech Connect (OSTI)

Small aromatic radicals such as C{sub 6}H{sub 5}, C{sub 6}H{sub 5}O and C{sub 6}H{sub 4} are key prototype species of their homologs. C{sub 6}H{sub 5} and its oxidation product, C{sub 6}H{sub 5}O are believed to be important intermediates which play a pivotal role in hydrocarbon combustion, particularly with regard to soot formation. Despite their fundamental importance, experimental data on the reaction mechanisms and reactivities of these species are very limited. For C{sub 6}H{sub 5}, most kinetic data except its reactions with NO and NO{sub 2}, were obtained by relative rate measurements. For C{sub 6}H{sub 5}O, the authors have earlier measured its fragmentation reaction producing C{sub 5}H{sub 5} + CO in shock waves. For C{sub 6}H{sub 4}, the only rate constant measured in the gas phase is its recombination rate at room temperature. The authors have proposed to investigate systematically the kinetics and mechanisms of this important class of molecules using two parallel laser diagnostic techniques--laser resonance absorption (LRA) and resonance enhanced multiphoton ionization mass spectrometry (REMPI/MS). In the past two years, study has been focused on the development of a new multipass adsorption technique--the {open_quotes}cavity-ring-down{close_quotes} technique for kinetic applications. The preliminary results of this study appear to be quite good and the sensitivity of the technique is at least comparable to that of the laser-induced fluorescence method.

Lin, M.C. [Emory Univ., Atlanta, GA (United States)

1993-12-01T23:59:59.000Z

293

E-Print Network 3.0 - ablation mid term Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sample search results for: ablation mid term Page: << < 1 2 3 4 5 > >> 1 Annals of Biomedical Engineering, Vol. 33, No. 10, October 2005 ( 2005) pp. 13521359 DOI: 10.1007...

294

COMPI,,PTATIONALMODEL OF SURFACE ABLATION FROM TOKAMAK DISRUPTIONS  

E-Print Network [OSTI]

, with U I = 9.1 MJ/m 2 heat load over a 100 Its duration. more typical of thermal disruptions and plasma to low kinetic energy particles (_ 100 eV). physics calculations which have little bearing on the final. Details of our atomic physics with plasma gun erosion tests on several metal targets, calculation compare

Harilal, S. S.

295

Kinetic models of opinion formation  

E-Print Network [OSTI]

We introduce and discuss certain kinetic models of (continuous) opinion formation involving both exchange of opinion between individual agents and diffusion of information. We show conditions which ensure that the kinetic model reaches non trivial stationary states in case of lack of diffusion in correspondence of some opinion point. Analytical results are then obtained by considering a suitable asymptotic limit of the model yielding a Fokker-Planck equation for the distribution of opinion among individuals.

G. Toscani

2006-05-17T23:59:59.000Z

296

Nonlinear effects in kinetic resolutions  

E-Print Network [OSTI]

KTRIC AMPLIFICATION IN THE JACOBSEN HYDROLYTIC KINET RESOLUTION OF RACEMIC EPOXIDES 20 Applicability of Homocompetitive Reaction Kinetics to the Jacobsen HKR Effect of Catalyst EE and Choice of Epoxide on Amplification in the Jacobsen HKR.... . . . . . . . . . . . . . . . . . Effect of Temperature on Amplification and Reaction Rate in the Jacobsen HKR . Effect of Low EE Catalyst Generation on Amplification in the Jacobsen HKR. . . . 21 21 25 26 27 30 31 TABLE OF CONTENTS (Continued) CHAPTER Page V AS...

Johnson, Derrell W.

1999-01-01T23:59:59.000Z

297

CT imaging during microwave ablation: Analysis of spatial and temporal tissue contraction  

SciTech Connect (OSTI)

Purpose: To analyze the spatial distribution and temporal development of liver tissue contraction during high-temperature ablation by using intraprocedural computed tomography (CT) imaging. Methods: A total of 46 aluminum fiducial markers were positioned in a 60 × 45 mm grid, in a single plane, around a microwave ablation antenna in each of six ex vivo bovine liver samples. Ablations were performed for 10 min at 100 W. CT data of the liver sample were acquired every 30 s during ablation. Fiducial motion between acquisitions was tracked in postprocessing and used to calculate measures of tissue contraction and contraction rates. The spatial distribution and temporal evolution of contraction were analyzed. Results: Fiducial displacement indicated that the zone measured postablation was 8.2 ± 1.8 mm (?20%) smaller in the radial direction and 7.1 ± 1.0 mm (?10%) shorter in the longitudinal direction than the preablation tissue dimension. Therefore, the total ablation volume was reduced from its preablation value by approximately 45%. Very little longitudinal contraction was noted in the distal portion of the ablation zone. Central tissues contracted more than 60%, which was near an estimated limit of ?70% based on initial water content. More peripheral tissues contracted only 15% in any direction. Contraction rates peaked during the first 60 s of heating with a roughly exponential decay over time. Conclusions: Ablation zones measured posttreatment are significantly smaller than the pretreatment tissue dimensions. Tissue contraction is spatially dependent, with the greatest effect occurring in the central ablation zone. Contraction rate peaks early and decays over time.

Liu, Dong; Brace, Christopher L., E-mail: clbrace@wisc.edu [Departments of Radiology and Biomedical Engineering, University of Wisconsin, Madison, Wisconsin 53705 (United States)

2014-11-01T23:59:59.000Z

298

Rapid Proton Transfer Mediated by a Strong Laser Field  

SciTech Connect (OSTI)

Kinetic energy distributions of H{sup +} ejected from a polyatomic molecule, anthraquinone, subjected to 60 fs, 800 nm laser pulses of intensity between 0.2 and 4.0x10{sup 14} W{center_dot}cm{sup -2}, reveal field-driven restructuring of the molecule prior to Coulomb explosion. Calculations demonstrate fast intramolecular proton migration into a field-dressed metastable potential energy minimum. The proton migration occurs in the direction perpendicular to the polarization of the laser field. Rapid field-mediated isomerization is an important new phenomenon in coupling of polyatomic molecules with intense lasers.

Markevitch, Alexei N.; Levis, Robert J. [Department of Chemistry, Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122 (United States); Romanov, Dmitri A. [Department of Physics, Center for Advanced Photonics Research, Temple University, Philadelphia, Pennsylvania 19122 (United States); Smith, Stanley M. [Department of Chemistry, Wayne State University, Detroit, Michigan 48202 (United States)

2006-04-28T23:59:59.000Z

299

Beamed Energy Propulsion by Means of Target Ablation  

SciTech Connect (OSTI)

This paper describes hundreds of pendulum tests examining the beamed energy conversion efficiency of different metal targets coated with multiple liquid enhancers. Preliminary testing used a local laser with photographic paper targets, with no liquid, water, canola oil, or methanol additives. Laboratory experimentation was completed at Wright-Patterson AFB using a high-powered laser, and ballistic pendulums of aluminum, titanium, or copper. Dry targets, and those coated with water, methanol and oil were repeatedly tested in laboratory conditions. Results were recorded on several high-speed digital video cameras, and the conversion efficiency was calculated. Paper airplanes successfully launched using BEP were likewise recorded.

Rosenberg, Benjamin A. [Hilton Head High School, Hilton Head Island, SC 29926 (United States)

2004-03-30T23:59:59.000Z

300

Free electron laser amplifier driven by an induction linac  

SciTech Connect (OSTI)

This paper discusses the use of a free-electron laser amplifier as a means of converting the kinetic energy of an electron beam into coherent radiation. In particular, the use of an induction linear accelerator is discussed. The motion of the elections in the tapered and untapered wiggler magnets is discussed as well as the beam emittance, and the radiation fields involved. (LSP)

Neil, V.K.

1986-06-03T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Conservation laws and laser cooling of atoms  

E-Print Network [OSTI]

The straightforward application of energy and linear momentum conservation to the absorption/emission of photons by atoms--first outlined by Schr\\"odinger in 1922--allows to establish the essential features of laser cooling of two levels atoms at low laser intensities. The minimum attainable average kinetic energy of the atoms depends on the ratio $\\Gamma/E_R$ between the natural linewidth and the recoil energy and tends to $E_R$ as $\\Gamma/E_R$ tends to zero. This treatment is valid for any value of the ratio $\\Gamma/E_R$ and contains the semiclassical theory of laser cooling as the limiting case in which $E_R\\ll \\Gamma$.

Giuliani, Giuseppe

2015-01-01T23:59:59.000Z

302

Laser Roadshow  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-SeriesFlickrinformationPostdocs space CombinedValuesRevolutionizingLaser

303

SLAM: a sodium-limestone concrete ablation model  

SciTech Connect (OSTI)

SLAM is a three-region model, containing a pool (sodium and reaction debris) region, a dry (boundary layer and dehydrated concrete) region, and a wet (hydrated concrete) region. The model includes a solution to the mass, momentum, and energy equations in each region. A chemical kinetics model is included to provide heat sources due to chemical reactions between the sodium and the concrete. Both isolated model as well as integrated whole code evaluations have been made with good results. The chemical kinetics and water migration models were evaluated separately, with good results. Several small and large-scale sodium limestone concrete experiments were simulated with reasonable agreement between SLAM and the experimental results. The SLAM code was applied to investigate the effects of mixing, pool temperature, pool depth and fluidization. All these phenomena were found to be of significance in the predicted response of the sodium concrete interaction. Pool fluidization is predicted to be the most important variable in large scale interactions.

Suo-Anttila, A.J.

1983-12-01T23:59:59.000Z

304

System and method of infrared matrix-assisted laser desorption/ionization mass spectrometry in polyacrylamide gels  

DOE Patents [OSTI]

A system and method for desorption and ionization of analytes in an ablation medium. In one embodiment, the method includes the steps of preparing a sample having analytes in a medium including at least one component, freezing the sample at a sufficiently low temperature so that at least part of the sample has a phase transition, and irradiating the frozen sample with short-pulse radiation to cause medium ablation and desorption and ionization of the analytes. The method further includes the steps of selecting a resonant vibrational mode of at least one component of the medium and selecting an energy source tuned to emit radiation substantially at the wavelength of the selected resonant vibrational mode. The medium is an electrophoresis medium having polyacrylamide. In one embodiment, the energy source is a laser, where the laser can be a free electron laser tunable to generate short-pulse radiation. Alternatively, the laser can be a solid state laser tunable to generate short-pulse radiation. The laser can emit light at various ranges of wavelength.

Haglund Jr., Richard F.; Ermer, David R.; Baltz-Knorr, Michelle Lee

2004-11-30T23:59:59.000Z

305

Tunable, diode side-pumped Er:YAG laser  

DOE Patents [OSTI]

A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 {micro}m, and is tunable over a 6 nm range near about 2.936 {micro}m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 {micro}m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 {micro}m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems. 4 figs.

Hamilton, C.E.; Furu, L.H.

1997-04-22T23:59:59.000Z

306

Laser thermoelastic generation in metals above the melt threshold  

SciTech Connect (OSTI)

An approach is presented for calculating thermoelastic generation of ultrasound in a metal plate exposed to nanosecond pulsed laser heating, sufficient to cause melting but not ablation. Detailed consideration is given to the spatial and temporal profiles of the laser pulse, penetration of the laser beam into the sample, the appearance and subsequent growth and then contraction of the melt pool, and the time dependent thermal conduction in the melt and surrounding solid throughout. The excitation of the ultrasound takes place during and shortly after the laser pulse and occurs predominantly within the thermal diffusion length of a micron or so beneath the surface. It is shown how, because of this, the output of the thermal simulations can be expressed as axially symmetric transient radial and normal surface force distributions. The epicentral displacement response to these force distributions is obtained by two methods, the one based on the elastodynamic Green's functions for plate geometry determined by the Cagniard generalized ray method and the other using a finite element numerical method. The two approaches are in very close agreement. Numerical simulations are reported on the epicentral displacement response of a 3.12 mm thick tungsten plate irradiated with a 4 ns pulsed laser beam with Gaussian spatial profile, at intensities below and above the melt threshold.

Every, A. G. [School of Physics, University of the Witwatersrand, PO Wits 2050 (South Africa)] [School of Physics, University of the Witwatersrand, PO Wits 2050 (South Africa); Utegulov, Z. N. [Department of Physics, School of Science and Technology, Nazarbayev University, Astana 010000 (Kazakhstan)] [Department of Physics, School of Science and Technology, Nazarbayev University, Astana 010000 (Kazakhstan); Veres, I. A. [RECENDT Research Center for Non-Destructive Testing GmbH, A-4040 Linz (Austria)] [RECENDT Research Center for Non-Destructive Testing GmbH, A-4040 Linz (Austria)

2013-11-28T23:59:59.000Z

307

Tunable, diode side-pumped Er: YAG laser  

DOE Patents [OSTI]

A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 .mu.m, and is tunable over a 6 nm range near about 2.936 .mu.m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 .mu.m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 .mu.m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems.

Hamilton, Charles E. (Bellevue, WA); Furu, Laurence H. (Modesto, CA)

1997-01-01T23:59:59.000Z

308

Hypersonic gasdynamic laser system  

SciTech Connect (OSTI)

This patent describes a visible, or near to mid infra-red, hypersonic gas dynamic laser system. It comprises: a hypersonic vehicle for carrying the hypersonic gas dynamic laser system, and also providing high energy ram air for thermodynamic excitation and supply of the laser gas; a laser cavity defined within the hypersonic vehicle and having a laser cavity inlet for the laser cavity formed by an opening in the hypersonic vehicle, such that ram air directed through the laser cavity opening supports gas dynamic lasing operations at wavelengths less than 10.6{mu} meters in the laser cavity; and an optical train for collecting the laser radiation from the laser cavity and directing it as a substantially collimated laser beam to an output aperture defined by an opening in the hypersonic vehicle to allow the laser beam to be directed against a target.

Foreman, K.M.; Maciulaitis, A.

1990-05-22T23:59:59.000Z

309

Laser machining of explosives  

DOE Patents [OSTI]

The invention consists of a method for machining (cutting, drilling, sculpting) of explosives (e.g., TNT, TATB, PETN, RDX, etc.). By using pulses of a duration in the range of 5 femtoseconds to 50 picoseconds, extremely precise and rapid machining can be achieved with essentially no heat or shock affected zone. In this method, material is removed by a nonthermal mechanism. A combination of multiphoton and collisional ionization creates a critical density plasma in a time scale much shorter than electron kinetic energy is transferred to the lattice. The resulting plasma is far from thermal equilibrium. The material is in essence converted from its initial solid-state directly into a fully ionized plasma on a time scale too short for thermal equilibrium to be established with the lattice. As a result, there is negligible heat conduction beyond the region removed resulting in negligible thermal stress or shock to the material beyond a few microns from the laser machined surface. Hydrodynamic expansion of the plasma eliminates the need for any ancillary techniques to remove material and produces extremely high quality machined surfaces. There is no detonation or deflagration of the explosive in the process and the material which is removed is rendered inert.

Perry, Michael D. (Livermore, CA); Stuart, Brent C. (Fremont, CA); Banks, Paul S. (Livermore, CA); Myers, Booth R. (Livermore, CA); Sefcik, Joseph A. (Tracy, CA)

2000-01-01T23:59:59.000Z

310

Chemical kinetics and combustion modeling  

SciTech Connect (OSTI)

The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

Miller, J.A. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

311

Laser programs highlights 1994  

SciTech Connect (OSTI)

This report provides highlights of the Lawrence Livermore National Laboratories` laser programs. Laser uses and technology assessment and utilization are provided.

NONE

1994-12-31T23:59:59.000Z

312

Laser Desorption Analysis | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser Desorption Analysis Laser Desorption Analysis EMSL offers a suite of instrumentation dedicated to understanding photoreactivity in the condensed phase, on surfaces, and at...

313

Laser Safety Management Policy Statement ............................................................................................................1  

E-Print Network [OSTI]

Laser Safety Management Policy Statement...........................................................2 Laser Users.............................................................................................................2 Unit Laser Safety Officer (ULSO

Davidson, Fordyce A.

314

Analysis of laser remote fusion cutting based on a mathematical model  

SciTech Connect (OSTI)

Laser remote fusion cutting is analyzed by the aid of a semi-analytical mathematical model of the processing front. By local calculation of the energy balance between the absorbed laser beam and the heat losses, the three-dimensional vaporization front can be calculated. Based on an empirical model for the melt flow field, from a mass balance, the melt film and the melting front can be derived, however only in a simplified manner and for quasi-steady state conditions. Front waviness and multiple reflections are not modelled. The model enables to compare the similarities, differences, and limits between laser remote fusion cutting, laser remote ablation cutting, and even laser keyhole welding. In contrast to the upper part of the vaporization front, the major part only slightly varies with respect to heat flux, laser power density, absorptivity, and angle of front inclination. Statistical analysis shows that for high cutting speed, the domains of high laser power density contribute much more to the formation of the front than for low speed. The semi-analytical modelling approach offers flexibility to simplify part of the process physics while, for example, sophisticated modelling of the complex focused fibre-guided laser beam is taken into account to enable deeper analysis of the beam interaction. Mechanisms like recast layer generation, absorptivity at a wavy processing front, and melt film formation are studied too.

Matti, R. S. [Department of Engineering Sciences and Mathematics, Luleå University of Technology, S-971 87 Luleå (Sweden); Department of Mechanical Engineering, College of Engineering, University of Mosul, Mosul (Iraq); Ilar, T.; Kaplan, A. F. H. [Department of Engineering Sciences and Mathematics, Luleå University of Technology, S-971 87 Luleå (Sweden)

2013-12-21T23:59:59.000Z

315

Femtosecond laser-induced periodic surface structure on the Ti-based nanolayered thin films  

SciTech Connect (OSTI)

Laser-induced periodic surface structures (LIPSSs) and chemical composition changes of Ti-based nanolayered thin films (Al/Ti, Ni/Ti) after femtosecond (fs) laser pulses action were studied. Irradiation is performed using linearly polarized Ti:Sapphire fs laser pulses of 40 fs pulse duration and 800 nm wavelength. The low spatial frequency LIPSS (LSFL), oriented perpendicular to the laser polarization with periods slightly lower than the irradiation wavelength, was typically formed at elevated laser fluences. On the contrary, high spatial frequency LIPSS (HSFL) with uniform period of 155 nm, parallel to the laser light polarization, appeared at low laser fluences, as well as in the wings of the Gaussian laser beam distribution for higher used fluence. LSFL formation was associated with the material ablation process and accompanied by the intense formation of nanoparticles, especially in the Ni/Ti system. The composition changes at the surface of both multilayer systems in the LSFL area indicated the intermixing between layers and the substrate. Concentration and distribution of all constitutive elements in the irradiated area with formed HSFLs were almost unchanged.

Petrovi?, Suzana M.; Gakovi?, B.; Peruško, D. [Institute of Nuclear Science—Vin?a, University of Belgrade, POB 522, 11001 Belgrade (Serbia)] [Institute of Nuclear Science—Vin?a, University of Belgrade, POB 522, 11001 Belgrade (Serbia); Stratakis, E. [Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, P.O. Box 1527, Gr-711 10 Heraklion (Greece) [Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, P.O. Box 1527, Gr-711 10 Heraklion (Greece); Department of Materials Science and Technology, University of Crete, 710 03 Heraklion, Crete (Greece); Bogdanovi?-Radovi?, I. [Ru?er Boškovi? Institute, P.O. Box 180, 10002 Zagreb (Croatia)] [Ru?er Boškovi? Institute, P.O. Box 180, 10002 Zagreb (Croatia); ?ekada, M. [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)] [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Fotakis, C. [Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, P.O. Box 1527, Gr-711 10 Heraklion (Greece) [Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, P.O. Box 1527, Gr-711 10 Heraklion (Greece); Department of Physics, University of Crete, 714 09 Heraklion, Crete (Greece); Jelenkovi?, B. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia)] [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia)

2013-12-21T23:59:59.000Z

316

Laser Faraday  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11LargeLaser Enables InexpensiveFaraday

317

Fiber Lasers  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI HomeTours, Programs and EventsFiber Lasers NIF

318

Single-Session Radiofrequency Ablation of Bilateral Lung Metastases  

SciTech Connect (OSTI)

Purpose: This retrospective study examined the feasibility and efficacy of bilateral lung radiofrequency ablation (RFA) performed in a single session. Methods: From 2002-2009, patients with bilateral lung metastases were treated by RFA, where possible in a single session under general anesthesia with CT guidance. The second lung was punctured only if no complications occurred after treatment of the first lung. Five lung metastases maximum per patient were treated by RFA and prospectively followed. The primary endpoint was the evaluation of acute and delayed complications. Secondary endpoints were calculation of hospitalization duration, local efficacy, median survival, and median time to tumor progression. Local efficacy was evaluated on CT or positron emission tomography (PET) CT. Results: Sixty-seven patients were treated for bilateral lung metastases with RFA (mean age, 62 years). Single-session treatment was not possible in 40 due to severe pneumothoraces (n = 24), bilateral pleural contact (n = 14), and operational exclusions (n = 2). Twenty-seven (41%) received single-session RFA of lesions in both lungs for 66 metastases overall. Fourteen unilateral and four bilateral pneumothoraces occurred (18 overall, 66.7%). Unilateral (n = 13) and bilateral (n = 2) chest tube drainage was required. Median hospitalization was 3 (range, 2-8) days. Median survival was 26 months (95% confidence interval (CI), 19-33). Four recurrences on RFA sites were observed (4 patients). Median time to tumor progression was 9.5 months (95% CI, 4.2-23.5). Conclusions: Although performing single-session bilateral lung RFA is not always possible due to pneumothoraces after RFA of first lung, when it is performed, this technique is safe and effective.

Palussiere, Jean, E-mail: palussiere@bergonie.org; Gomez, Fernando; Cannella, Matthieu; Ferron, Stephane; Descat, Edouard [Institut Bergonie, Department of Radiology, Regional Cancer Centre (France); Fonck, Marianne [Institut Bergonie, Department of Digestive Oncology (France); Brouste, Veronique [Institut Bergonie, Clinical and Epidemiological Research Unit (France); Avril, Antoine [Institut Bergonie, Department of Surgery (France)

2012-08-15T23:59:59.000Z

319

Analysis of strained surface layers of ZnO single crystals after irradiation with intense femtosecond laser pulses  

SciTech Connect (OSTI)

Structural modifications of ZnO single crystals that were created by the irradiation with femtosecond laser pulses at fluences far above the ablation threshold were investigated with micro-Raman spectroscopy. After light-matter interaction on the femtosecond time scale, rapid cooling and the pronounced thermal expansion anisotropy of ZnO are likely to cause residual strains of up to 1.8% and also result in the formation of surface cracks. This process relaxes the strain only partially and a strained surface layer remains. Our findings demonstrate the significant role of thermoelastic effects for the irradiation of solids with intense femtosecond laser pulses.

Schneider, Andreas; Sebald, Kathrin; Voss, Tobias [Semiconductor Optics, Institute of Solid State Physics, University of Bremen, D-28359 Bremen (Germany)] [Semiconductor Optics, Institute of Solid State Physics, University of Bremen, D-28359 Bremen (Germany); Wolverson, Daniel [Nanoscience Group, Department of Physics, University of Bath, BA2 7AY Bath (United Kingdom)] [Nanoscience Group, Department of Physics, University of Bath, BA2 7AY Bath (United Kingdom); Hodges, Chris; Kuball, Martin [Center for Device Thermography and Reliability (CDTR), H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)] [Center for Device Thermography and Reliability (CDTR), H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)

2013-05-27T23:59:59.000Z

320

Method for continuous control of composition and doping of pulsed laser deposited films  

DOE Patents [OSTI]

A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

Lowndes, Douglas H. (Knoxville, TN); McCamy, James W. (Knoxville, TN)

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Method for continuous control of composition and doping of pulsed laser deposited films by pressure control  

DOE Patents [OSTI]

A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

Lowndes, Douglas H. (Knoxville, TN); McCamy, James W. (Knoxville, TN)

1996-01-01T23:59:59.000Z

322

Laser-induced synthesis and decay of Tritium under exposure of solid targets in heavy water  

E-Print Network [OSTI]

The processes of laser-assisted synthesis of Tritium nuclei and their laser-induced decay in cold plasma in the vicinity of solid targets (Au, Ti, Se, etc.) immersed into heavy water are experimentally realized at peak laser intensity of 10E10-10E13 Watts per square centimeter. Initial stages of Tritium synthesis and their laser-induced beta-decay are interpreted on the basis of non-elastic interaction of plasma electrons having kinetic energy of 5-10 eV with nuclei of Deuterium and Tritium, respectively.

E. V. Barmina; P. G. Kuzmin; S. F. Timashev; G. A. Shafeev

2013-06-03T23:59:59.000Z

323

Laser-induced synthesis and decay of Tritium under exposure of solid targets in heavy water  

E-Print Network [OSTI]

The processes of laser-assisted synthesis of Tritium nuclei and their laser-induced decay in cold plasma in the vicinity of solid targets (Au, Ti, Se, etc.) immersed into heavy water are experimentally realized at peak laser intensity of 10E10-10E13 Watts per square centimeter. Initial stages of Tritium synthesis and their laser-induced beta-decay are interpreted on the basis of non-elastic interaction of plasma electrons having kinetic energy of 5-10 eV with nuclei of Deuterium and Tritium, respectively.

Barmina, E V; Timashev, S F; Shafeev, G A

2013-01-01T23:59:59.000Z

324

Cholecystokinin-Assisted Hydrodissection of the Gallbladder Fossa during FDG PET/CT-guided Liver Ablation  

SciTech Connect (OSTI)

A 68-year-old female with colorectal cancer developed a metachronous isolated fluorodeoxyglucose-avid (FDG-avid) segment 5/6 gallbladder fossa hepatic lesion and was referred for percutaneous ablation. Pre-procedure computed tomography (CT) images demonstrated a distended gallbladder abutting the segment 5/6 hepatic metastasis. In order to perform ablation with clear margins and avoid direct puncture and aspiration of the gallbladder, cholecystokinin was administered intravenously to stimulate gallbladder contraction before hydrodissection. Subsequently, the lesion was ablated successfully with sufficient margins, of greater than 1.0 cm, using microwave with ultrasound and FDG PET/CT guidance. The patient tolerated the procedure very well and was discharged home the next day.

Tewari, Sanjit O., E-mail: tewaris@mskcc.org [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States); Petre, Elena N., E-mail: petree@mskcc.org [Memorial Sloan-Kettering Cancer Center, Interventional Radiology Service, Department of Radiology (United States); Osborne, Joseph, E-mail: osbornej@mskcc.org [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States)] [Memorial Sloan-Kettering Cancer Center, Molecular Imaging and Therapy Service, Department of Radiology (United States); Sofocleous, Constantinos T., E-mail: sofoclec@mskcc.org [Memorial Sloan-Kettering Cancer Center, Interventional Radiology Service, Department of Radiology (United States)

2013-12-15T23:59:59.000Z

325

Kinetic Modeling and Thermodynamic Closure Approximation of ...  

E-Print Network [OSTI]

Oct 5, 2007 ... Kinetic Modeling and Thermodynamic Closure. Approximation of Liquid Crystal Polymers. Haijun Yu. Program in Applied and Computational ...

2007-10-03T23:59:59.000Z

326

Real-time magnetic resonance imagingguided radiofrequency atrial ablation and visualization of lesion formation at 3 Tesla  

E-Print Network [OSTI]

of lesion formation at 3 Tesla Gaston R. Vergara, MD,* Sathya Vijayakumar, MS,* Eugene G. Kholmovski, Ph. In this study, we report a novel 3-Tesla RT -RI based porcine RF ablation model and visuali- zation of lesion-Tesla RT MRI-based catheter ablation and lesion visualization system. METHODS RF energy was delivered

Utah, University of

327

Narrow gap laser welding  

DOE Patents [OSTI]

A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables.

Milewski, John O. (Santa Fe, NM); Sklar, Edward (Santa Fe, NM)

1998-01-01T23:59:59.000Z

328

Narrow gap laser welding  

DOE Patents [OSTI]

A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables. 34 figs.

Milewski, J.O.; Sklar, E.

1998-06-02T23:59:59.000Z

329

Short wavelength laser  

DOE Patents [OSTI]

A short wavelength laser is provided that is driven by conventional-laser pulses. A multiplicity of panels, mounted on substrates, are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path. When the panels are illuminated by the conventional-laser pulses, single pass EUV or soft x-ray laser pulses are produced.

Hagelstein, P.L.

1984-06-25T23:59:59.000Z

330

Longitudinal discharge laser baffles  

DOE Patents [OSTI]

The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam. 1 fig.

Warner, B.E.; Ault, E.R.

1994-06-07T23:59:59.000Z

331

Ultrafast Large Area Micropattern Generation in Non-absorbing Polymer Thin-Films by Pulsed Laser Diffraction  

E-Print Network [OSTI]

We report an ultrafast, parallel and beyond-the-master micro-patterning technique for ultrathin (30 nm-400 nm) non-absorbing polymer films by diffraction of a laser light through a two dimensional periodic aperture. The redistribution of laser energy absorbed by the substrate causes self-organization of polymer thin-film in the form of wrinkle like surface relief structures caused by localized melting and freezing of the thin-film. Unlike the conventional laser ablation and laser writing processes, low laser fluence is employed to only passively swell the polymer as a pre-ablative process without the loss of material, and without absorption/reaction with the incident radiation. Self-organization in the thin polymer film aided by the diffraction pattern produces micro-structures made up of thin raised lines. These regular microstructures have far more complex morphologies than the mask geometry and very narrow line widths that can be an order of magnitude smaller than the openings in the mask. The microstructure morphology is easily modulated by changing the film thickness, aperture size and geometry and by changing the diffraction pattern, e.g., by changing the aperture-substrate distance.

Ankur Verma; Ashutosh Sharma; Giridhar U. Kulkarni

2011-01-27T23:59:59.000Z

332

In situ investigation of formation of self-assembled nanodomain structure in lithium niobate after pulse laser irradiation  

SciTech Connect (OSTI)

The evolution of the self-assembled quasi-regular micro- and nanodomain structures after pulse infrared laser irradiation was studied by in situ optical observation. The average periods of the structures are much less than the sizes of the laser spots. The polarization reversal occurs through covering of the whole irradiated area by the nets of the spatially separated nanodomain chains and microdomain rays--''hatching effect.'' The main stages of the anisotropic nanodomain kinetics: nucleation, growth, and branching, have been singled out. The observed abnormal domain kinetics was attributed to the action of the pyroelectric field arising during cooling after laser heating.

Shur, V. Ya.; Kuznetsov, D. K.; Mingaliev, E. A.; Yakunina, E. M.; Lobov, A. I.; Ievlev, A. V. [Ferroelectric Laboratory, Institute of Physics and Applied Mathematics, Ural State University, Lenin Ave. 51, Ekaterinburg 620083 (Russian Federation)

2011-08-22T23:59:59.000Z

333

14CME Kinetic Energy and Mass Kinetic energy is the energy that a  

E-Print Network [OSTI]

14CME Kinetic Energy and Mass Kinetic energy is the energy that a body has by virtue of its mass the table by determining the value of the missing entries using the formula for Kinetic Energy. Problem 2: What is the minimum and maximum range for the observed kinetic energies for the 10 CMEs? The largest

334

Hypersonic nonequilibrium Navier-Stokes solutions over an ablating graphite nosetip  

SciTech Connect (OSTI)

The general boundary conditions, including mass and energy balances, of chemically equilibrated or nonequilibrated gas adjacent to ablating surfaces have been derived. A computer procedure based on these conditions was developed and interfaced with the Navier-Stokes solver GASP (General Aerodynamics Simulation Program). A test case with a proposed hypersonic test-vehicle configuration and associated freestream conditions was developed. The solutions of the GASP code with various surface boundary conditions were obtained and compared with those of the ASCC (ABRES Shape Change) code, and the effect of nonequilibrium gas as well as surface chemistry on surface heating and ablation rate were examined. 22 refs.

Chen, Y.K.; Henline, W.D. [National Aeronautics and Space Administration, Ames Research Center, Moffett Field, CA (United States)

1994-09-01T23:59:59.000Z

335

Shock-less interactions of ablation streams in tungsten wire array z-pinches  

SciTech Connect (OSTI)

Shock-less dynamics were observed during the ablation phase in tungsten wire array experiments carried out on the 1.4 MA, 240 ns MAGPIE generator at Imperial College London. This behaviour contrasts with the shock structures which were seen to dominate in previous experiments on aluminium arrays [Swadling et al., Phys. Plasmas 20, 022705 (2013)]. In this paper, we present experimental results and make comparisons both with calculations of the expected mean free paths for collisions between the ablation streams and with previously published Thomson scattering measurements of the plasma parameters in these arrays [Harvey-Thompson et al., Phys. Plasmas 19, 056303 (2012)].

Swadling, G. F.; Lebedev, S. V.; Hall, G. N.; Suzuki-Vidal, F.; Burdiak, G.; Harvey-Thompson, A. J.; Bland, S. N.; De Grouchy, P.; Khoory, E.; Pickworth, L.; Skidmore, J.; Suttle, L. [The Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom)] [The Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom)

2013-06-15T23:59:59.000Z

336

Comparing the use of mid-infrared versus far-infrared lasers for mitigating damage growth on fused silica  

SciTech Connect (OSTI)

Laser-induced growth of optical damage can limit component lifetime and, therefore, increase operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, we quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {mu}m) versus far-IR (10.6 {mu}m) lasers in mitigating damage growth on fused silica surfaces. The nonlinear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda}=4.6 {mu}m, while far-IR laser heating is well described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on IR radiometry, as well as subsurface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally ablative conditions. Based on our FOM, we show that, for cracks up to at least 500 {mu}m in depth, mitigation with a 4.6 {mu}m mid-IR laser is more efficient than mitigation with a 10.6 {mu}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {mu}m in depth.

Yang, Steven T.; Matthews, Manyalibo J.; Elhadj, Selim; Cooke, Diane; Guss, Gabriel M.; Draggoo, Vaughn G.; Wegner, Paul J.

2010-05-10T23:59:59.000Z

337

Estimating The Thermodynamics And Kinetics Of Chlorinated Hydrocarbon...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Estimating The Thermodynamics And Kinetics Of Chlorinated Hydrocarbon Degradation. Estimating The Thermodynamics And Kinetics Of Chlorinated Hydrocarbon Degradation. Abstract: Many...

338

Challenges and Progress Toward a Commercial Kinetic Hydropower System  

E-Print Network [OSTI]

Challenges and Progress Toward a Commercial Kinetic Hydropower System for its kinetic hydropower devices, and has made precise measurements

Walter, M.Todd

339

Nonstoichiometric material transfer in the pulsed laser deposition of LaAlO{sub 3}  

SciTech Connect (OSTI)

Inequivalent angular distributions have been found for La and Al in the ablation plume from LaAlO{sub 3} single crystal targets using a KrF laser during pulsed laser deposition. Angular distributions and stoichiometries in the condensate were measured and reveal decidedly nonstoichiometric transfer from target to substrate over most of the angular range. Composition varied dramatically for plume angles parallel to the long axis of the laser spot with the on-axis position exhibiting a peak in the La/Al atom ratio at {approx}1.5. The distributions were more diffuse in the perpendicular direction. Stoichiometric LaAlO{sub 3} was found in the condensate only at an extreme off-axis position.

Droubay, T. C.; Qiao, L.; Kaspar, T. C.; Engelhard, M. H.; Shutthanandan, V.; Chambers, S. A. [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

2010-09-20T23:59:59.000Z

340

Laser-assisted nanomaterial deposition, nanomanufacturing, in situ monitoring and associated apparatus  

DOE Patents [OSTI]

Laser-assisted apparatus and methods for performing nanoscale material processing, including nanodeposition of materials, can be controlled very precisely to yield both simple and complex structures with sizes less than 100 nm. Optical or thermal energy in the near field of a photon (laser) pulse is used to fabricate submicron and nanometer structures on a substrate. A wide variety of laser material processing techniques can be adapted for use including, subtractive (e.g., ablation, machining or chemical etching), additive (e.g., chemical vapor deposition, selective self-assembly), and modification (e.g., phase transformation, doping) processes. Additionally, the apparatus can be integrated into imaging instruments, such as SEM and TEM, to allow for real-time imaging of the material processing.

Mao, Samuel S; Grigoropoulos, Costas P; Hwang, David J; Minor, Andrew M

2013-11-12T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Preliminary Design of Laser - induced Breakd own Spectroscopy for Proto - MPEX  

SciTech Connect (OSTI)

Laser-induced breakdown spectroscopy (LIBS) is a technique for measuring surface matter composition. LIBS is performed by focusing laser radiation onto a target surface, ablating the surface, forming a plasma, and analyzing the light produced. LIBS surface analysis is a possible diagnostic for characterizing plasma-facing materials in ITER. Oak Ridge National Laboratory (ORNL) has enabled the initial installation of a laser-induced breakdown spectroscopy diagnostic on the prototype Material-Plasma Exposure eXperiment (Proto-MPEX), which strives to mimic the conditions found at the surface of the ITER divertor. This paper will discuss the LIBS implementation on Proto-MPEX, preliminary design of the fiber optic LIBS collection probe, and the expected results.

Shaw, Guinevere C [ORNL] [ORNL; Biewer, T.M. [Oak Ridge National Laboratory (ORNL)] [Oak Ridge National Laboratory (ORNL); Martin, Madhavi Z [ORNL] [ORNL; Martin, Rodger Carl [ORNL] [ORNL

2014-01-01T23:59:59.000Z

342

Evaluation of kinetic phosphorescence analysis for the determination of uranium  

SciTech Connect (OSTI)

In the past, New Brunswick Laboratory (NBL) has used a fluorometric method for the determination of sub-microgram quantities of uranium. In its continuing effort to upgrade and improve measurement technology, NBL has evaluated the commercially-available KPA-11 kinetic phosphorescence analyzer (Chemchek, Richland, WA). The Chemchek KPA-11 is a bench-top instrument which performs single-measurement, quench-corrected analyses for trace uranium. It incorporates patented kinetic phosphorimetry techniques to measure and analyze sample phosphorescence as a function of time. With laser excitation and time-corrected photon counting, the KPA-11 has a lower detection limit than conventional fluorometric methods. Operated with a personal computer, the state-of-the-art KPA-11 offers extensive time resolution and phosphorescence lifetime capabilities for additional specificity. Interferences are thereby avoided while obtaining precise measurements. Routine analyses can be easily and effectively accomplished, with the accuracy and precision equivalent to the pulsed-laser fluorometric method presently performed at NBL, without the need for internal standards. Applications of kinetic phosphorimetry at NBL include the measurement of trace level uranium in retention tank, waste samples, and low-level samples. It has also been used to support other experimental activities at NBL by the measuring of nanogram amounts of uranium contamination (in blanks) in isotopic sample preparations, and the determining of elution curves of different ion exchange resins used for uranium purification. In many cases, no pretreatment of samples was necessary except to fume them with nitric acid, and then to redissolve and dilute them to an appropriate concentration with 1 M HNO{sub 3} before measurement. Concentrations were determined on a mass basis ({micro}g U/g of solution), but no density corrections were needed since all the samples (including the samples used for calibration) were in the same density matrix (1 M HNO{sub 3}). A statistical evaluation of the determination of uranium using kinetic phosphorimetry is described in this report, along with a discussion of the method, and an evaluation of the use of plastic versus quartz cuvettes. Measurement with a precision of {+-} 3--4% relative standard deviation (RSD) and an accuracy of better than {+-} 2% relative difference (RD) are obtained in the 0.0006 to 5 {micro}g U/g-solution range. The instrument detection limit is 0.04 ppb (4 x 10{sup {minus}5} {micro}g U/g solution) using quartz cells, and 0.11 ppb (11 x 10{sup {minus}5} {micro}g U/g solution) using disposable methacrylate cuvettes.

Croatto, P.V.; Frank, I.W.; Johnson, K.D.; Mason, P.B.; Smith, M.M.

1997-12-01T23:59:59.000Z

343

Flyer Acceleration by Pulsed Ion Beam Ablation and Application for Space Propulsion  

SciTech Connect (OSTI)

Flyer acceleration by ablation plasma pressure produced by irradiation of intense pulsed ion beam has been studied. Acceleration process including expansion of ablation plasma was simulated based on fluid model. And interaction between incident pulsed ion beam and a flyer target was considered as accounting stopping power of it. In experiments, we used ETIGO-II intense pulsed ion beam generator with two kinds of diodes; 1) Magnetically Insulated Diode (MID, power densities of <100 J/cm2) and 2) Spherical-focused Plasma Focus Diode (SPFD, power densities of up to 4.3 kJ/cm2). Numerical results of accelerated flyer velocity agreed well with measured one over wide range of incident ion beam energy density. Flyer velocity of 5.6 km/s and ablation plasma pressure of 15 GPa was demonstrated by the present experiments. Acceleration of double-layer target consists of gold/aluminum was studied. For adequate layer thickness, such a flyer target could be much more accelerated than a single layer. Effect of waveform of ion beam was also examined. Parabolic waveform could accelerate more efficiently than rectangular waveform. Applicability of ablation propulsion was discussed. Specific impulse of 7000{approx}8000 seconds and time averaged thrust of up to 5000{approx}6000N can be expected. Their values can be controllable by changing power density of incident ion beam and pulse duration.

Harada, Nobuhiro; Buttapeng, Chainarong; Yazawa, Masaru [Department of Electrical Engineering, Nagaoka University of Technology, 1603 Kamitomioka, Nagaoka 940-2188 (Japan); Kashine, Kenji [Department of Electrical and Electronic Engineering, Kagoshima National College of Technology, 1460-1 Shinko, Hayato-cho, Aira-gun, Kagoshima 899-5193 (Japan); Jiang Weihua; Yatsui, Kiyoshi [Extreme Energy Density Research Institute, Nagaoka University of Technology, 1603 Kamitomioka, Nagaoka 940-2188 (Japan)

2004-02-04T23:59:59.000Z

344

Increasing Temporal Resolution in Greenland Ablation Estimation Using Passive and Active Microwave Data  

E-Print Network [OSTI]

Increasing Temporal Resolution in Greenland Ablation Estimation Using Passive and Active Microwave of these measurements provides an increased understanding of the diurnal melt cycle over Greenland and estimation of the melt profile. I. INTRODUCTION Accurate estimation of the mass balance of the Greenland ice sheet

Long, David G.

345

RIS-M-2219 A numerical code for computing the ablated state of a  

E-Print Network [OSTI]

RISÃ?-M-2219 PELREF A numerical code for computing the ablated state of a refuelling pellet C.4. Flow parameters at the sonic radius 11 2.5. The asymptotic solutions 13 3. COMPUTATIONAL CODE of the existing neutral shielding model , etc., it should be desirable to have such a computational code at our

346

A Dual-Armed Robotic System for Intraoperative Ultrasound Guided Hepatic Ablative Therapy:A  

E-Print Network [OSTI]

A Dual-Armed Robotic System for Intraoperative Ultrasound Guided Hepatic Ablative Therapy, we propose the use of a dual robotic arm system that manages both ultrasound manipulation and needle guidance. We report a prototype of the dual arm system and a comparative performance analysis between

Camesano, Terri

347

Photo-inducible cell ablation in Caenorhabditis elegans using the genetically encoded singlet  

E-Print Network [OSTI]

oxygen generating protein miniSOG Yingchuan B. Qia,1 , Emma J. Garrena , Xiaokun Shub,c , Roger Y. Tsienc-inducible and tissue-selective cell ablation using a genetically encoded photosensitizer, miniSOG (mini singlet oxygen generator). miniSOG is a newly engineered fluo- rescent protein of 106 amino acids that generates singlet

Tsien, Roger Y.

348

ablated first-wall materials: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ablated first-wall materials First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Tungsten as first wall...

349

The ablation zone in northeast Greenland: ice types, albedos and impurities  

E-Print Network [OSTI]

), Box 156, NO-9171 Longyearbyen, Norway E-mail: carl.egede.boggild@unis.no 2 Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195-1640, USA 3 Canadian Forest Service, Northern in the ablation zone (Hanna and others, 2005; Box and others, 2006). The major source of energy for melting ice

Warren, Stephen

350

Percutaneous Intraductal Radiofrequency Ablation is a Safe Treatment for Malignant Biliary Obstruction: Feasibility and Early Results  

SciTech Connect (OSTI)

Purpose. Previous clinical studies have shown the safety and efficacy of this novel radiofrequency ablation catheter when used for endoscopic palliative procedures. We report a retrospective study with the results of first in man percutaneous intraductal radiofrequency ablation in patients with malignant biliary obstruction. Methods. Thirty-nine patients with inoperable malignant biliary obstruction were included. These patients underwent intraductal biliary radiofrequency ablation of their malignant biliary strictures following external biliary decompression with an internal-external biliary drainage. Following ablation, they had a metal stent inserted. Results. Following this intervention, there were no 30-day mortality, hemorrhage, bile duct perforation, bile leak, or pancreatitis. Of the 39 patients, 28 are alive and 10 patients are dead with a median survival of 89.5 (range 14-260) days and median stent patency of 84.5 (range 14-260) days. One patient was lost to follow-up. All but one patient had their stent patent at the time of last follow-up or death. One patient with stent blockage at 42 days postprocedure underwent percutaneous transhepatic drain insertion and restenting. Among the patients who are alive (n = 28) the median stent patency was 92 (range 14-260) days, whereas the patients who died (n = 10) had a median stent patency of 62.5 (range 38-210) days. Conclusions. In this group of patients, it appears that this new approach is feasible and safe. Efficacy remains to be proven in future, randomized, prospective studies.

Mizandari, Malkhaz [Tbilisi State Medical University, Department of Radiology (Georgia); Pai, Madhava, E-mail: madhava.pai@imperial.ac.uk; Xi Feng [Imperial College, London, Hammersmith Hospital Campus, Department of Surgery (United Kingdom); Valek, Vlastimil; Tomas, Andrasina [University Hospital Brno Bohunice, Department of Radiology (Czech Republic); Quaretti, Pietro [IRCCS Policlinico San Matteo, Department of Radiology (Italy); Golfieri, Rita; Mosconi, Cristina [University of Bologna, Department of Radiology, Policlinico S. Orsola-Malpighi (Italy); Ao Guokun [The 309 Hospital of Chinese PLA, Department of Radiology (China); Kyriakides, Charis [Imperial College, London, Hammersmith Hospital Campus, Department of Surgery (United Kingdom); Dickinson, Robert [Imperial College London, Department of Bioengineering (United Kingdom); Nicholls, Joanna; Habib, Nagy, E-mail: nagy.habib@imperial.ac.uk [Imperial College, London, Hammersmith Hospital Campus, Department of Surgery (United Kingdom)

2013-06-15T23:59:59.000Z

351

Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation  

SciTech Connect (OSTI)

Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO{sub 2} insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve.

Tsoumakidou, Georgia, E-mail: gtsoumakidou@yahoo.com; Garnon, Julien, E-mail: juliengarnon@gmail.com; Ramamurthy, Nitin, E-mail: nitin_ramamurthy@hotmail.com; Buy, Xavier, E-mail: xbuy@ymail.com; Gangi, Afshin, E-mail: gangi@unistra.fr [University Hospital of Strasbourg (France)] [University Hospital of Strasbourg (France)

2013-12-15T23:59:59.000Z

352

ImageGuided Ex vivo Liver Ablation by Unfocused Ultrasound using Passive Cavitation Detection  

E-Print Network [OSTI]

Image­Guided Ex vivo Liver Ablation by Unfocused Ultrasound using Passive Cavitation Detection echogenicity from image brightness. Passively detected acoustic emissions are used to quantify cavitation and cavitation. The latter two quantities can potentially be monitored noninvasively and used as a surrogate

Mast, T. Douglas

353

Sustained Growth of the Ex Vivo Ablation Zones' Critical Short Axis Using Gas-cooled Radiofrequency Applicators  

SciTech Connect (OSTI)

Purpose: To evaluate the ablation zones created with a gas-cooled bipolar radiofrequency applicator performed on ex vivo bovine liver tissue. Materials and Methods: A total of 320 ablations with an internally gas-cooled bipolar radiofrequency applicator were performed on fresh ex vivo bovine liver tissue, varying the ablation time (5, 10, 15, and 20 min), power (20, 30, 40, and 50 W), and gas pressure of the CO{sub 2} used for cooling (585, 600, 615, 630, 645 psi), leading to a total of 80 different parameter combinations. Size and shape of the white coagulation zone were assessed. Results: The largest complete ablation zone was achieved after 20 min of implementing 50 W and 645 psi, resulting in a short axis of mean 46 {+-} 1 mm and a long axis of 56 {+-} 2 mm (mean {+-} standard deviation). Short-axis diameters increased between 5 and 20 min of ablation time at 585 psi (increase of the short axis was 45% at 30 W, 29% at 40 W, and 39% at 50 W). This increase was larger at 645 psi (113% at 30 W, 67% at 40 W, and 70% at 50 W). Macroscopic assessment and NADH (nicotinamide adenine dinucleotide) staining revealed incompletely ablated tissue along the needle track in 18 parameter combinations including low-power settings (20 and 30 W) and different cooling levels and ablation times. Conclusion: Gas-cooled radiofrequency applicators increase the short-axis diameter of coagulation in an ex vivo setting if appropriate parameters are selected.

Rempp, Hansjoerg, E-mail: hansjoerg.rempp@med.uni-tuebingen.de [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Scharpf, Marcus [Insitute of Pathology, Eberhard Karls University of Tuebingen, Department of General Pathology and Pathological Anatomy (Germany); Voigtlaender, Matthias [ERBE Elektromedizin GmbH (Germany); Schraml, Christina; Schmidt, Diethard [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Fend, Falko [Insitute of Pathology, Eberhard Karls University of Tuebingen, Department of General Pathology and Pathological Anatomy (Germany); Claussen, Claus D. [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany); Enderle, Markus D. [ERBE Elektromedizin GmbH (Germany); Pereira, Philippe L. [Klinik fuer Radiologie, Minimalinvasive Therapien und Nuklearmedizin (Germany); Clasen, Stephan [Eberhard Karls University of Tuebingen, Department of Diagnostic and Interventional Radiology (Germany)

2011-02-15T23:59:59.000Z

354

Simulations of laser imprint for Nova experiments and for ignition capsules. Revision 1  

SciTech Connect (OSTI)

In direct drive ICF, nonuniformities in laser illumination seed ripples at the ablation front in a process called ``imprint``. These nonuniformities grow during the capsule implosion and, if initially large enough, can penetrate the capsule shell, impede ignition, or degrade burn. Imprint has been simulated for recent experiments performed on the Nova laser at LLNL examining a variety of beam smoothing conditions. Most used laser intensities similar to the early part of an ignition capsule pulse shape, 1 {approx_equal} 10{sup 13} W/cm{sup 2} . The simulations matched most of the measurements of imprint modulation. The effect of imprint upon National Ignition Facility (NIF) direct drive ignition capsules has also been simulated. Imprint is predicted to give modulation comparable to an intrinsic surface finish of {approximately}10 nm RMS. Modulation growth was examined using the Haan [Phys. Rev. A {bold 39}, 5812 (1989)] model, with linear growth factors as a function of spherical harmonic mode number obtained from an analytic dispersion relation. Ablation front amplitudes are predicted to become substantially nonlinear, so that saturation corrections are large. Direct numerical simulations of two-dimensional multimode growth were also performed. The capsule shell is predicted to remain intact, which gives a basis for believing that ignition can be achieved. 27 refs., 10 figs.

Weber, S.V.; Glendinning, S.G.; Kalantar, D.H.; Key, M.H.; Remington, B.A.; Rothenberg, J.L. [Lawrence Livermore National Lab., CA (United States); Wolfrum, E. [Rutherford Appleton Lab., Chilton (United Kingdom); Verdon, C.P.; Knauer, J.P. [Rochester Univ., NY (United States). Lab. for Laser Energetics

1996-12-01T23:59:59.000Z

355

Simulations of laser imprint for Nova experiments and for ignition capsules  

SciTech Connect (OSTI)

In direct drive ICF, nonuniformities in laser illumination seed ripples at the ablation front in a process called imprint. These non nonuniformities grow during the capsule implosion and, if initially large enough, can penetrate the capsule shell, impede ignition, or degrade burn. Imprint has been simulated for recent experiments performed on the Nova laser at LLNL examining a variety of beam smoothing conditions. Most used laser intensities similar to the early part of an ignition capsule pulse shape, I=10X13 W/cm3. The simulations matched most of the measurements of imprint modulation. The effect of imprint upon National Ignition Facility (NIF) direct drive ignition capsules has also been simulated. Imprint is predicted to give modulation comparable to an intrinsic surface finish of 10 nm RMS. Modulation growth was examined using the Haan model, with linear growth as a function of spherical harmonic mode number obtained from an analytic dispersion relation. Ablation front amplitudes are predicted to become substantially nonlinear, so that saturation corrections are large. Direct numerical simulations of two- dimensional multimode growth were also performed. The capsule shell is predicted to remain intact, which gives a basis for believing that ignition can be achieved.

Weber, S.V.; Glendinning, S.G.; Kalantar, D.H.; Key, M.H.; Remington, B.A.; Rothenberg, J.E.; Wolfrum, E.; Verdon, C.P.; Knauer, J.P.

1996-11-08T23:59:59.000Z

356

Usefulness of Guiding Needles for Radiofrequency Ablative Treatment of Liver Tumors  

SciTech Connect (OSTI)

Purpose. To evaluate the usefulness of a guiding needle for radiofrequency (RF) ablative treatment of liver tumors. Methods. Forty-two patients, 38-78 years old (57 {+-} 17), with 42 liver tumors (18 HCC, 24 colon cancer metastases) underwent RF ablation using a 14-gauge guiding needle with an external insulated sheath in which any 18-gauge or smaller needle can be placed, including a specially designed 3.5 cm LeVeen RF electrode. One guiding needle was used in 20 tumors to provide biopsy and RF treatment in a single puncture. Three to five guiding needles were loaded in 22 tumors measuring 35 to 64 mm in their largest diameter before starting RF treatment requiring multiple overlapping RF applications. Results. In the 20 RF treatments combined with biopsy, the biopsy was always contributive. Because of pre-positioning of the sheath, postbiopsy modifications (bleeding or air artifacts) did not hinder subsequent RF treatment. The 22 large tumors received 5 to 12 RF applications (mean = 6.8) through the three to five preloaded guiding needles. The RF ablation zones measured 46 to 94 mm (mean 55) in their largest dimension, with ablative margins in all cases. After 8 to 32 months (mean = 20), 14 of the 22 tumors are considered completely destroyed on computed tomography follow-up and one tumor seeding has been found. Conclusion. The Leveen CoAccess needle allows precise tumor targeting when treating large tumors requiring multiple RF applications. It allows biopsies combined with RF ablation through a single tract.

Baere, Thierry de, E-mail: debaere@igr.fr; Rehim, Mohamed Abdel; Teriitheau, Christophe; Deschamps, Frederic; Lapeyre, Mathieu; Dromain, Clarisse [Institut Gustave Roussy, Departement d'Imagerie Medicale (France); Boige, Valerie; Ducreux, Michel [Institut Gustave Roussy, Departement de medicine (France); Elias, Dominique [Institut Gustave Roussy, Departement de Chirurgie (France)

2006-08-15T23:59:59.000Z

357

Laser studies of chemical reaction and collision processes  

SciTech Connect (OSTI)

This work has concentrated on several interrelated projects in the area of laser photochemistry and photophysics which impinge on a variety of questions in combustion chemistry and general chemical kinetics. Infrared diode laser probes of the quenching of molecules with {open_quotes}chemically significant{close_quotes} amounts of energy in which the energy transferred to the quencher has, for the first time, been separated into its vibrational, rotational, and translational components. Probes of quantum state distributions and velocity profiles for atomic fragments produced in photodissociation reactions have been explored for iodine chloride.

Flynn, G. [Columbia Univ., New York, NY (United States)

1993-12-01T23:59:59.000Z

358

Copper bromide vapour laser with a pulse repetition rate up to 700 kHz  

SciTech Connect (OSTI)

The results of the experimental study of a copper bromide vapour laser at high repetition rates of regular pump pulses are presented. A record-high pulse repetition rate of 700 kHz is attained for lasing at self-terminating transitions in copper atoms. To analyse the obtained results, use is made of the data of numerical modelling of the plasma kinetics in the phase of pumping and discharge afterglow. (lasers)

Nekhoroshev, V O; Fedorov, V F; Evtushenko, Gennadii S; Torgaev, S N

2012-10-31T23:59:59.000Z

359

FIREBALL: Fusion Ignition Rocket Engine with Ballistic Ablative Lithium Liner  

SciTech Connect (OSTI)

Thermo-nuclear fusion may be the key to a high Isp, high specific power propulsion system. In a fusion system energy is liberated within, and imparted directly to, the propellant. In principle, this can overcome the performance limitations inherent in systems that require thermal power transfer across a material boundary, and/or multiple power conversion stages (NTR, NEP). A thermo-nuclear propulsion system, which attempts to overcome some of the problems inherent in the Orion concept, is described. A dense FRC plasmoid is accelerated to high velocity (in excess of 500 km/s) and is compressed into a detached liner (pulse unit). The kinetic energy of the FRC is converted into thermal and magnetic-field energy, igniting a fusion burn in the magnetically confined plasma. The fusion reaction serves as an ignition source for the liner, which is made out of detonable materials. The energy liberated in this process is converted to thrust by a pusher-plate, as in the classic Orion concept. However with this concept, the vehicle does not carry a magazine of autonomous pulse-units. By accelerating a second, heavier FRC, which acts as a piston, right behind the first one, the velocity required to initiate the fusion burn is greatly reduced.

Martin, Adam K.; Eskridge, Richard H.; Lee, Michael H. [Propulsion Research Center, NASA Marshall Space Flight Center XD22, Huntsville, AL 35812 (United States); Fimognari, Peter J. [Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

2006-01-20T23:59:59.000Z

360

Kinetic Modeling of Microbiological Processes  

SciTech Connect (OSTI)

Kinetic description of microbiological processes is vital for the design and control of microbe-based biotechnologies such as waste water treatment, petroleum oil recovery, and contaminant attenuation and remediation. Various models have been proposed to describe microbiological processes. This editorial article discusses the advantages and limiation of these modeling approaches in cluding tranditional, Monod-type models and derivatives, and recently developed constraint-based approaches. The article also offers the future direction of modeling researches that best suit for petroleum and environmental biotechnologies.

Liu, Chongxuan; Fang, Yilin

2012-09-17T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Laser-assisted electrochemistry  

SciTech Connect (OSTI)

The effect of laser irradiation on electrodeposition processes has been investigated. These studies demonstrated that the addition of laser irradiation to an electroplating process can dramatically enhance plating rates and current efficiencies, as well as improve the morphology of the resultant electrodeposit. During the course of these investigations, the mechanism for the laser enhancement of electrodeposition processes was determined. Experimental evidence was obtained to show that laser irradiation of the substrate results in increased metal ion concentrations at the surface of the electrode due to a laser-induced Soret effect. The laser-induced Soret effect has important implications for laser-assisted electrochemical processing. The increase in the surface concentration of ions allows efficient electrodeposition from dilute solutions. As such, laser- assisted electrodeposition may develop into an environmentally conscious manufacturing process by reducing waste and limiting worker exposure to toxic chemicals.

Glenn, D.F.

1995-05-01T23:59:59.000Z

362

Along the Laser Beampath  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

9 20 | Next | Last Back to Index NIF Laser Bay Seen from above, each of NIF's two identical laser bays has two clusters of 48 beamlines, one on either side of the utility spine...

363

Laser particle sorter  

DOE Patents [OSTI]

Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

Martin, J.C.; Buican, T.N.

1987-11-30T23:59:59.000Z

364

Along the Laser Beampath  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

has been installed in the preamplifier modules (PAMs) at the front end of the NIF laser system. The spatial shapers can obscure the laser light at programmed locations within...

365

Combinatorial pulsed laser deposition of doped yttrium iron garnet films on yttrium aluminium garnet  

SciTech Connect (OSTI)

We investigate the crystalline growth of yttrium iron garnet (YIG) films doped with bismuth (Bi) and cerium (Ce) by combinatorial pulsed laser deposition, co-ablating a YIG target and either a Bi{sub 2}O{sub 3} or a CeO{sub 2} target, for applications in microwave and optical communications. Substrate temperature is critical for crystalline growth of YIG with simultaneous inclusion of Bi in the garnet lattice, whereas Ce is not incorporated in the garnet structure, but forms a separate CeO{sub 2} phase.

Sposito, A., E-mail: as11g10@orc.soton.ac.uk; Eason, R. W. [Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom); Gregory, S. A.; Groot, P. A. J. de [Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom)

2014-02-07T23:59:59.000Z

366

Short wavelength laser  

DOE Patents [OSTI]

A short wavelength laser (28) is provided that is driven by conventional-laser pulses (30, 31). A multiplicity of panels (32), mounted on substrates (34), are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path (42). When the panels (32) are illuminated by the conventional-laser pulses (30, 31), single pass EUV or soft x-ray laser pulses (44, 46) are produced.

Hagelstein, Peter L. (Livermore, CA)

1986-01-01T23:59:59.000Z

367

Innovative lasers for uranium isotope separation. [Progress report  

SciTech Connect (OSTI)

Copper vapor lasers have important applications to uranium atomic vapor laser isotope separation (AVLIS). The authors have spent the first two years of their project investigating two innovative methods of exciting/pumping copper vapor lasers which have the potential to improve the efficiency and scaling of large laser systems used in uranium isotope separation. Experimental research has focused on the laser discharge kinetics of (1) microwave, and (2) electron beam excitation/pumping of large-volume copper vapor lasers. During the first year, the experiments have been designed and constructed and initial data has been taken. During the second year these experiments have been diagnosed. Highlights of some of the second year results as well as plans for the future include the following: Microwave resonant cavity produced copper vapor plasmas at 2.45 GHz, have been investigated. A CW (0--500 W) signal heats and vaporizes the copper chloride to provide the atomic copper vapor. A pulsed (5 kW, 0.5--5kHz) signal is added to the incoming CW signal via a hybrid mixer to excite the copper states to the laser levels. An enhancement of the visible radiation has been observed during the pulsed pardon of the signal. Electrical probe measurements have been implemented on the system to verify the results of the electromagnetic model formulated last year. Laser gain measurements have been initiated with the use of a commercial copper vapor laser. Measurements of the spatial profile of the emission are also currently being made. The authors plan to increase the amount of pulsed microwave power to the system by implementing a high power magnetron. A laser cavity will be designed and added to this system.

Brake, M.L.; Gilgenbach, R.M.

1991-06-01T23:59:59.000Z

368

Laser bottom hole assembly  

DOE Patents [OSTI]

There is provided for laser bottom hole assembly for providing a high power laser beam having greater than 5 kW of power for a laser mechanical drilling process to advance a borehole. This assembly utilizes a reverse Moineau motor type power section and provides a self-regulating system that addresses fluid flows relating to motive force, cooling and removal of cuttings.

Underwood, Lance D; Norton, Ryan J; McKay, Ryan P; Mesnard, David R; Fraze, Jason D; Zediker, Mark S; Faircloth, Brian O

2014-01-14T23:59:59.000Z

369

LaserFest Celebration  

SciTech Connect (OSTI)

LaserFest was the yearlong celebration, during 2010, of the 50th anniversary of the demonstration of the first working laser. The goals of LaserFest were: to highlight the impact of the laser in its manifold commercial, industrial and medical applications, and as a tool for ongoing scientific research; to use the laser as one example that illustrates, more generally, the route from scientific innovation to technological application; to use the laser as a vehicle for outreach, to stimulate interest among students and the public in aspects of physical science; to recognize and honor the pioneers who developed the laser and its many applications; to increase awareness among policymakers of the importance of R&D funding as evidenced by such technology as lasers. One way in which LaserFest sought to meet its goals was to encourage relevant activities at a local level all across the country -- and also abroad -- that would be identified with the larger purposes of the celebration and would carry the LaserFest name. Organizers were encouraged to record and advertise these events through a continually updated web-based calendar. Four projects were explicitly detailed in the proposals: 1) LaserFest on the Road; 2) Videos; 3) Educational material; and 4) Laser Days.

Dr. Alan Chodos; Elizabeth A. Rogan

2011-08-25T23:59:59.000Z

370

Observation of a crossover in kinetic aggregation of Palladium colloids  

E-Print Network [OSTI]

We use field emission scanning electron microscope (FE-SEM) to investigate the growth of palladium colloids over the surface of thin films of WO3/glass. The film is prepared by Pulsed Laser Deposition (PLD) at different temperatures. A PdCl2 (aq) droplet is injected on the surface and in the presence of steam hydrogen the droplet is dried through a reduction reaction process. Two distinct aggregation regimes of palladium colloids are observed over the substrates. We argue that the change in aggregation dynamics emerges when the measured water drop Contact Angel (CA) for the WO3/glass thin films passes a certain threshold value, namely CA = 46 degrees, where a crossover in kinetic aggregation of palladium colloids occurs. Our results suggest that the mass fractal dimension of palladium aggregates follows a power-law behavior. The fractal dimension (Df) in the fast aggregation regime, where the measured CA values vary from 27 up to 46 degrees, according to different substrate deposition temperatures, is Df = 1.75 (0.02). This value of Df is in excellent agreement with kinetic aggregation of other colloidal systems in fast aggregation regime. Whereas for the slow aggregation regime, with CA = 58 degrees, the fractal dimension changes abruptly to Df=1.92 (0.03). We have also used a modified Box-Counting method to calculate fractal dimension of gray-level images and observe that the crossover at around CA = 46 degrees remains unchanged.

M. Ghafari; M. Ranjbar; S. Rouhani

2014-12-27T23:59:59.000Z

371

Chemical Kinetic Research on HCCI & Diesel Fuels  

Broader source: Energy.gov (indexed) [DOE]

improved gasoline surrogate fuels for HCCI engines * Development of very efficient software to reduce the size of detailed chemical kinetic models for transportation fuels...

372

CLEERS Coordination & Development of Catalyst Process Kinetic...  

Broader source: Energy.gov (indexed) [DOE]

& coordinate DOE research efforts (CLEERS Coordination) * Develop detailed technical data required to simulate energy efficient emission controls (LNT & SCR Kinetics, Sulfur &...

373

Kinetic bounding volume hierarchies for deformable objects  

E-Print Network [OSTI]

We present novel algorithms for updating bounding volume hierarchies of objects undergoing arbitrary deformations. Therefore, we introduce two new data structures, the kinetic AABB tree and the kinetic BoxTree. The event-based approach of the kinetic data structures framework enables us to show that our algorithms are optimal in the number of updates. Moreover, we show a lower bound for the total number of BV updates, which is independent of the number of frames. We used our kinetic bounding volume hierarchies for collision detection and performed a comparison with the classical bottomup update method. The results show that our algorithms perform up to ten times faster in practically relevant scenarios.

Gabriel Zachmann; Tu Clausthal

2006-01-01T23:59:59.000Z

374

The Fractional Kinetic Equation and Thermonuclear Functions  

E-Print Network [OSTI]

The paper discusses the solution of a simple kinetic equation of the type used for the computation of the change of the chemical composition in stars like the Sun. Starting from the standard form of the kinetic equation it is generalized to a fractional kinetic equation and its solutions in terms of H-functions are obtained. The role of thermonuclear functions, which are also represented in terms of G- and H-functions, in such a fractional kinetic equation is emphasized. Results contained in this paper are related to recent investigations of possible astrophysical solutions of the solar neutrino problem.

H. J. Haubold; A. M. Mathai

2000-01-16T23:59:59.000Z

375

CLEERS Coordination & Development of Catalyst Process Kinetic...  

Energy Savers [EERE]

CLEERS Coordination & Development of Catalyst Process Kinetic Data - Pres. 1: Coordination of CLEERS Project; Pres. 2: ORNL Research on LNT Sulfation & Desulfation CLEERS...

376

Combustion kinetics and reaction pathways  

SciTech Connect (OSTI)

This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

Klemm, R.B.; Sutherland, J.W. [Brookhaven National Laboratory, Upton, NY (United States)

1993-12-01T23:59:59.000Z

377

Kinetics of actinide complexation reactions  

SciTech Connect (OSTI)

Though the literature records extensive compilations of the thermodynamics of actinide complexation reactions, the kinetics of complex formation and dissociation reactions of actinide ions in aqueous solutions have not been extensively investigated. In light of the central role played by such reactions in actinide process and environmental chemistry, this situation is somewhat surprising. The authors report herein a summary of what is known about actinide complexation kinetics. The systems include actinide ions in the four principal oxidation states (III, IV, V, and VI) and complex formation and dissociation rates with both simple and complex ligands. Most of the work reported was conducted in acidic media, but a few address reactions in neutral and alkaline solutions. Complex formation reactions tend in general to be rapid, accessible only to rapid-scan and equilibrium perturbation techniques. Complex dissociation reactions exhibit a wider range of rates and are generally more accessible using standard analytical methods. Literature results are described and correlated with the known properties of the individual ions.

Nash, K.L.; Sullivan, J.C.

1997-09-01T23:59:59.000Z

378

Cost effective nanostructured copper substrates prepared with ultrafast laser pulses for explosives detection using surface enhanced Raman scattering  

SciTech Connect (OSTI)

Ultrafast laser pulses induced surface nanostructures were fabricated on a copper (Cu) target through ablation in acetone, dichloromethane, acetonitrile, and chloroform. Surface morphological information accomplished from the field emission scanning electron microscopic data demonstrated the diversities of ablation mechanism in each case. Fabricated Cu substrates were utilized exultantly to investigate the surface plasmon (localized and propagating) mediated enhancements of different analytes using surface enhance Raman scattering (SERS) studies. Multiple utility of these substrates were efficiently demonstrated by collecting the SERS data of Rhodamine 6G molecule and two different secondary explosive molecules such as 5-amino-3-nitro-l,2,4-triazole and trinitrotoluene on different days which were weeks apart. We achieved significant enhancement factors of >10{sup 5} through an easily adoptable cleaning procedure.

Hamad, Syed [School of Physics, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India); Podagatlapalli, G. Krishna; Soma, Venugopal Rao, E-mail: svrsp@uohyd.ernet.in, E-mail: soma-venu@yahoo.com [Advanced Center of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India); Mohiddon, Md. Ahamad [Center for Nanotechnology, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India)

2014-06-30T23:59:59.000Z

379

Comparison of three methods for control of postoperative pain in dogs after total ear canal ablation with lateral bulla osteotomy  

E-Print Network [OSTI]

This prospective study compared three methods of postoperative pain control in dogs undergoing total ear canal ablation with lateral bulla osteotomy. The hypothesis was that systemic opioids in conjunction with preoperative local nerve blocks would...

Buback, Janice Lynelle

2012-06-07T23:59:59.000Z

380

Multiple temperature kinetic model and gas-kinetic method for hypersonic non-equilibrium flow computations  

E-Print Network [OSTI]

Multiple temperature kinetic model and gas-kinetic method for hypersonic non-equilibrium flow. For the non-equilibrium flow computations, i.e., the nozzle flow and hypersonic rarefied flow over flat plate-kinetic method; Hypersonic and rarefied flows 1. Introduction The development of aerospace technology has

Xu, Kun

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Testing the kinetic energy functional: Kinetic energy density as a density functional  

E-Print Network [OSTI]

is to the exchange-correlation energy as a functional of the density. A large part of the total energy, the kinetic contexts. For finite systems these forms integrate to the same global ki- netic energy, but they differTesting the kinetic energy functional: Kinetic energy density as a density functional Eunji Sim

Burke, Kieron

382

X-ray laser  

DOE Patents [OSTI]

An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

Nilsen, Joseph (Livermore, CA)

1991-01-01T23:59:59.000Z

383

ORION laser target diagnostics  

SciTech Connect (OSTI)

The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

Bentley, C. D.; Edwards, R. D.; Andrew, J. E.; James, S. F.; Gardner, M. D.; Comley, A. J.; Vaughan, K.; Horsfield, C. J.; Rubery, M. S.; Rothman, S. D.; Daykin, S.; Masoero, S. J.; Palmer, J. B.; Meadowcroft, A. L.; Williams, B. M.; Gumbrell, E. T.; Fyrth, J. D.; Brown, C. R. D.; Hill, M. P.; Oades, K. [Plasma Physics Department, Atomic Weapons Establishment, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); and others

2012-10-15T23:59:59.000Z

384

Kinetic Theory of Dynamical Systems  

E-Print Network [OSTI]

It is generally believed that the dynamics of simple fluids can be considered to be chaotic, at least to the extent that they can be modeled as classical systems of particles interacting with short range, repulsive forces. Here we give a brief introduction to those parts of chaos theory that are relevant for understanding some features of non-equilibrium processes in fluids. We introduce the notions of Lyapunov exponents, Kolmogorov-Sinai entropy and related quantities using some simple low-dimensional systems as "toy" models of the more complicated systems encountered in the study of fluids. We then show how familiar methods used in the kinetic theory of gases can be employed for explicit, analytical calculations of the largest Lyapunov exponent and KS entropy for dilute gases composed of hard spheres in d dimensions. We conclude with a brief discussion of interesting, open problems.

R. van Zon; H. van Beijeren; J. R. Dorfman

1999-06-24T23:59:59.000Z

385

ADVANCES IN ENVIRONMENTAL REACTION KINETICS AND THERMODYNAMICS  

E-Print Network [OSTI]

1262 ADVANCES IN ENVIRONMENTAL REACTION KINETICS AND THERMODYNAMICS: LONG-TERM FATE thermodynamic and kinetic data is available with regard to the formation of these mixed metal precipitate phases to six months from the initial addition of aqueous nickel. Additionally, we have determined thermodynamic

Sparks, Donald L.

386

Chemical kinetics and oil shale process design  

SciTech Connect (OSTI)

Oil shale processes are reviewed with the goal of showing how chemical kinetics influences the design and operation of different processes for different types of oil shale. Reaction kinetics are presented for organic pyrolysis, carbon combustion, carbonate decomposition, and sulfur and nitrogen reactions.

Burnham, A.K.

1993-07-01T23:59:59.000Z

387

Preparation of germanium doped plasma polymerized coatings as ICF target ablators  

SciTech Connect (OSTI)

Targets for Inertial Confinement Fusion (ICF) experiments at the Lawrence Livermore National Laboratory (LLNL) utilize an organic (CH) ablator coating prepared by plasma polymerization. Some of these experiments require a mid-Z dopant in the ablator coating to modify the opacity of the shell. Bromine had been used in the past, but the surface finish of brominated CH degrades rapidly with time upon exposure to air. This paper describes the preparation and characterization of plasma polymer layers containing germanium as a dopant at concentrations of between 1.25 and 2.25 atom percent. The coatings are stable in air and have an rms surface roughness of 7--9 nm (modes 10--1,000) which is similar to that obtained with undoped coatings. High levels of dopant result in cracking of the inner mandrel during target assembly. Possible explanations for the observed cracking behavior will be discussed.

Brusasco, R.M.; Saculla, M.D.; Cook, R.C.

1994-10-05T23:59:59.000Z

388

Laser system using ultra-short laser pulses  

DOE Patents [OSTI]

A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

Dantus, Marcos (Okemos, MI); Lozovoy, Vadim V. (Okemos, MI); Comstock, Matthew (Milford, MI)

2009-10-27T23:59:59.000Z

389

Kinetic advantage of controlled intermediate nuclear fusion  

SciTech Connect (OSTI)

The dominated process of controlled fusion is to let nuclei gain enough kinetic energy to overcome Coulomb barrier. As a result, a fusion scheme can consider two factors in its design: to increase kinetic energy of nuclei and to alter the Coulomb barrier. Cold Fusion and Hot fusion are all one-factor schemes while Intermediate Fusion is a twofactors scheme. This made CINF kinetically superior. Cold Fusion reduces deuteron-deuteron distance, addressing Coulomb barrier, and Hot Fusion heat up plasma into extreme high temperature, addressing kinetic energy. Without enough kinetic energy made Cold Fusion skeptical. Extreme high temperature made Hot Fusion very difficult to engineer. Because CIFN addresses both factors, CIFN is a more promising technique to be industrialized.

Guo Xiaoming [Physics and Computer Science Department, Wilfrid Laurier University, Waterloo, Ontario, N2L 3C5 (Canada)

2012-09-26T23:59:59.000Z

390

A Comparison of Direct Heating During Radiofrequency and Microwave Ablation in Ex Vivo Liver  

SciTech Connect (OSTI)

This study was designed to determine the magnitude and spatial distribution of temperature elevations when using 480 kHz RF and 2.45 GHz microwave energy in ex vivo liver models. A total of 60 heating cycles (20 s at 90 W) were performed in normal, RF-ablated, and microwave-ablated liver tissues (n = 10 RF and n = 10 microwave in each tissue type). Heating cycles were performed using a 480-kHz generator and 3-cm cooled-tip electrode (RF) or a 2.45-GHz generator and 14-gauge monopole (microwave) and were designed to isolate direct heating from each energy type. Tissue temperatures were measured by using fiberoptic thermosensors 5, 10, and 15 mm radially from the ablation applicator at the depth of maximal heating. Power delivered, sensor location, heating rates, and maximal temperatures were compared using mixed effects regression models. No significant differences were noted in mean power delivered or thermosensor locations between RF and microwave heating groups (P > 0.05). Microwaves produced significantly more rapid heating than RF at 5, 10, and 15 mm in normal tissue (3.0 vs. 0.73, 0.85 vs. 0.21, and 0.17 vs. 0.09 Degree-Sign C/s; P < 0.05); and at 5 and 10 mm in ablated tissues (2.3 {+-} 1.4 vs. 0.7 {+-} 0.3, 0.5 {+-} 0.3 vs. 0.2 {+-} 0 Degree-Sign C/s, P < 0.05). The radial depth of heating was {approx}5 mm greater for microwaves than RF. Direct heating obtained with 2.45-GHz microwave energy using a single needle-like applicator is faster and covers a larger volume of tissue than 480-kHz RF energy.

Andreano, Anita; Brace, Christopher L., E-mail: clbrace@wisc.edu [University of Wisconsin, Department of Radiology (United States)

2013-04-15T23:59:59.000Z

391

Radiofrequency Ablation of Lung Tumours with the Patient Under Thoracic Epidural Anaesthesia  

SciTech Connect (OSTI)

Radiofrequency ablation of lung tumours is a curative technique that is newly considered being offered to nonsurgical patients. It is of major interest because it enables local destruction of the tumour without surgery and spares healthy parenchyma. However, some patients have previous serious respiratory failure, thus ruling out mechanical ventilation. To operate with the patient under thoracic epidural is an answer to this problem. Our experience shows that the procedure is able to be performed completely without converting to general anaesthesia.

Pouliquen, Cassiopee; Kabbani, Youssef, E-mail: kabbani@bergonie.org; Saignac, Pierre; Gekiere, Jean-Pierre [Institut Bergonie, Department of Anesthesiology and Intensive Care, Regional Cancer Centre (France); Palussiere, Jean [Institut Bergonie, Department of Interventional Radiology, Regional Cancer Centre (France)

2011-02-15T23:59:59.000Z

392

Nonoperable Recurrent Renal Cell Carcinoma: Management with Embolization and CT-Guided RF Ablation  

SciTech Connect (OSTI)

We report the case of a 59-year-old male who underwent embolization and computed-tomography-guided radiofrequency ablation of a recurrent renal cell carcinoma that developed after radical nephrectomy in contiguity to the inferior vena cava. The alternative of a new operation was rejected because of the proximity of the tumor to the vessel and percutaneous approach seemed to be the better solution.

Thanos, Loukas, E-mail: loutharad@yahoo.com; Pomomi, Maria; Mylona, Sophia; Ntai, Sparti; Mpatakis, Nikolaos ['Korgialenio Benakio' Red Cross Hospital of Athens, Department of Radiology (Greece)

2006-08-15T23:59:59.000Z

393

Renal Tumors: Technical Success and Early Clinical Experience with Radiofrequency Ablation of 18 Tumors  

SciTech Connect (OSTI)

Purpose. To evaluate the feasibility, safety, and technical efficacy of image-guided radiofrequency ablation (RFA) for the treatment of small peripheral renal tumors and to report our early results with this treatment modality. Methods. Twenty-two RFA sessions for 18 tumors were performed in 11 patients with renal tumors. Indications included coexistent morbidity, high surgical or anesthetic risk, solitary kidney, and hereditary predisposition to renal cell carcinoma. Ten patients had CT-guided percutaneous RFA performed on an outpatient basis. One patient had open intraoperative ultrasound-guided RFA. Technical success was defined as elimination of areas that enhanced at imaging within the entire tumor. With the exception of one patient with renal insufficiency who required gadolinium-enhanced MRI, the remaining patients underwent contrast-enhanced CT for post-treatment follow-up assessment. Follow-up was performed after 2-4 weeks and then at 3, 6, 12 months, and every 12 months thereafter. Results. Fourteen (78%) of 18 tumors were successfully ablated with one session. Three of the remaining four tumors required two sessions for successful ablation. One tumor will require a third session for areas of persistent enhancement. Mean patient age was 72.82 {+-} 10.43 years. Mean tumor size was 1.95 {+-} 0.79 cm. Mean follow-up time was 10.91 months. All procedures were performed without any major complications. Conclusions. Our early experience with percutaneous image-guided radiofrequency ablation demonstrates it to be a feasible, safe, noninvasive, and effective treatment of small peripheral renal tumors.

Sabharwal, Rohan, E-mail: rohan50000@yahoo.com; Vladica, Philip [Westmead Hospital, Department of Radiology (Australia)

2006-04-15T23:59:59.000Z

394

Kinetic and mechanistic studies of free-radical reactions in combustion  

SciTech Connect (OSTI)

Combustion is driven by energy-releasing chemical reactions. Free radicals that participate in chain reactions carry the combustion process from reactants to products. Research in chemical kinetics enables us to understand the microscopic mechanisms involved in individual chemical reactions as well as to determine the rates at which they proceed. Both types of information are required for an understanding of how flames burn, why engines knock, how to minimize the production of pollutants, and many other important questions in combustion. In this program the authors emphasize accurate measurements over wide temperature ranges of the rates at which ubiquitous free radicals react with stable molecules. The authors investigate a variety of OH, CN, and CH + stable molecule reactions important to fuel conversion, emphasizing application of the extraordinarily precise technique of laser photolysis/continuous-wave laser-induced fluorescence (LP/cwLIF). This precision enables kinetic measurements to serve as mechanistic probes. Since considerable effort is required to study each individual reaction, prudent selection is critical. Two factors encourage selection of a specific reaction: (1) the rates and mechanisms of the subject reaction are required input to a combustion model; and (2) the reaction is a chemical prototype which, upon characterization, will provide fundamental insight into chemical reactivity, facilitate estimation of kinetic parameters for similar reactions, and constrain and test the computational limits of reaction-rate theory. Most studies performed in this project satisfy both conditions.

Tully, F.P. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

395

Feasibility of Respiratory Triggering for MR-Guided Microwave Ablation of Liver Tumors Under General Anesthesia  

SciTech Connect (OSTI)

We obtained clear and reproducible MR fluoroscopic images and temperature maps for MR image-guided microwave ablation of liver tumors under general anesthesia without suspending the artificial ventilation. Respiratory information was directly obtained from air-way pressure without a sensor on the chest wall. The trigger signal started scanning of one whole image with a spoiled gradient echo sequence. The delay time before the start of scanning was adjusted to acquire the data corresponding to the k-space center at the maximal expiratory phase. The triggered images were apparently clearer than the nontriggered ones and the location of the liver was consistent, which made targeting of the tumor easy. MR temperature images, which were highly susceptible to the movement of the liver, during microwave ablation using a proton resonance frequency method, could be obtained without suspending the artificial ventilation. Respiratory triggering technique was found to be useful for MR fluoroscopic images and MR temperature monitoring in MR-guided microwave ablation of liver tumors under general anesthesia.

Morikawa, Shigehiro, E-mail: morikawa@belle.shiga-med.ac.jp; Inubushi, Toshiro [Shiga University of Medical Science, Seta Tsukinowa-cho, Ohtsu, Molecular Neuroscience Research Center (Japan); Kurumi, Yoshimasa; Naka, Shigeyuki; Sato, Koichiro; Demura, Koichi; Tani, Tohru [Shiga University of Medical Science, Department of Surgery (Japan); Haque, Hasnine A [GE-Yokogawa Medical Systems (Japan)

2004-08-15T23:59:59.000Z

396

Evaluation of pneumatic nebulization and ns-laser ablation ICP-MS for bulk elemental analysis and 2-dimensional  

E-Print Network [OSTI]

ID: JA-ART-12-2013-050387 Article Type: Paper Date Submitted by the Author: 12-Dec-2013 Complete List Brussels, Belgium.25 Electronic Supplementary Information (ESI) available Introduction The continuously

Claeys, Philippe

397

UV-Laser-Ablation-Combustion-GC-IRMS a tool for on-line analysis of intra-annual  

E-Print Network [OSTI]

it is combusted to CO2 at 700 C. Inside the reactor an oxidized copper wire provides the oxygen for the combustion (analyst) document measuring direction (analyst) high resolution post-analysis photographs for relating a high level of congruity. A conservative estimate of the precision is ± 0.24 . Comparison with a more

398

Direct chemical analysis of frozen ice cores by UV-laser ablation ICPMS Wolfgang Muller,*a  

E-Print Network [OSTI]

mm long ice (b, c); its `tongue-like' extension through the cell door has a Peltier element clamped DOI: 10.1039/c1ja10242g Cryo-cell UV-LA-ICPMS is a new technique for direct chemical analysis analysis at cell UV-LA-ICPMS setup used

Royal Holloway, University of London

399

Thomson parabola spectrometry for gold laser-generated plasmas  

SciTech Connect (OSTI)

The plasma generated from thin gold films irradiated in high vacuum at high intensity ({approx}10{sup 15} W/cm{sup 2}) laser shot is characterized in terms of ion generation through time-of-flight techniques and Thomson parabola spectrometry. Gold ions and protons, accelerated in forward direction by the electric field developed in non-equilibrium plasma, have been investigated. Measurements, performed at PALS laboratory, give information about the gold charge states distributions, the ion energy distributions and the proton acceleration driven as a function of film thickness, laser parameters, and angular emission. The ion diagnostics of produced plasma in forward direction permits to understand some mechanisms developed during its expansion kinetics. The role of the focal position of a laser beam with respect to the target surface, plasma properties, and the possibility to accelerate protons up to energies above 3 MeV has been presented and discussed.

Torrisi, L.; Cutroneo, M.; Ando, L. [Physics Department of Messina University, V.le F. S. D'Alcontres 31, 9816 S. Agata (Italy); Ullschmied, J. [Institute of Physics, ASCR, v.v.i., 182 21 Prague 8 (Czech Republic)

2013-02-15T23:59:59.000Z

400

Laser assisted high entropy alloy coating on aluminum: Microstructural evolution  

SciTech Connect (OSTI)

High entropy alloy (Al-Fe-Co-Cr-Ni) coatings were synthesized using laser surface engineering on aluminum substrate. Electron diffraction analysis confirmed the formation of solid solution of body centered cubic high entropy alloy phase along with phases with long range periodic structures within the coating. Evolution of such type of microstructure was a result of kinetics associated with laser process, which generates higher temperatures and rapid cooling resulting in retention of high entropy alloy phase followed by reheating and/or annealing in subsequent passes of the laser track giving rise to partial decomposition. The partial decomposition resulted in formation of precipitates having layered morphology with a mixture of high entropy alloy rich phases, compounds, and long range ordered phases.

Katakam, Shravana; Joshi, Sameehan S.; Mridha, Sanghita; Mukherjee, Sundeep; Dahotre, Narendra B., E-mail: Narendra.Dahotre@unt.edu [Department of Materials Science and Engineering, University of North Texas, 1150 Union Circle, 305310 Denton, Texas 76203-5017 (United States)

2014-09-14T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

LASER SAFETY POLICY Policy Statement  

E-Print Network [OSTI]

LASER SAFETY POLICY Policy Statement Each department that acquires or operates lasers for use in laboratories or research is responsible for reporting laser acquisition to the Office of Laboratory Safety, selecting a departmental deputy laser safety officer, mandating training for its laser operators

Vertes, Akos

402

Laser-PlasmaWakefield Acceleration with Higher Order Laser Modes  

E-Print Network [OSTI]

Design considerations for a laser-plasma linear collider,"E.Esarey, and W.P.Leemans, "Free-electron laser driven bythe LBNL laser-plasma accelerator," in Proc. Adv. Acc. Con.

Geddes, C.G.R.

2011-01-01T23:59:59.000Z

403

Long-term Kinetics of Uranyl Desorption from Sediments Under...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

term Kinetics of Uranyl Desorption from Sediments Under Advective Conditions. Long-term Kinetics of Uranyl Desorption from Sediments Under Advective Conditions. Abstract: Long-term...

404

Direct Visualization of Initial SEI Morphology and Growth Kinetics...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Initial SEI Morphology and Growth Kinetics During Lithium Deposition by in situ Electrochemical Direct Visualization of Initial SEI Morphology and Growth Kinetics During Lithium...

405

Structure, Kinetics, and Thermodynamics of the Aqueous Uranyl...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Kinetics, and Thermodynamics of the Aqueous Uranyl(VI) Cation. Structure, Kinetics, and Thermodynamics of the Aqueous Uranyl(VI) Cation. Abstract: Molecular simulation techniques...

406

Uncertainty analysis of multi-rate kinetics of uranium desorption...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Uncertainty analysis of multi-rate kinetics of uranium desorption from sediments. Uncertainty analysis of multi-rate kinetics of uranium desorption from sediments. Abstract: A...

407

Global Optimization of Chemical Reactors and Kinetic Optimization  

E-Print Network [OSTI]

Model; 3-D; Monolith; Reactor; Optimization Introduction TheAngeles Global Optimization of Chemical Reactors and KineticGlobal Optimization of Chemical Reactors and Kinetic

ALHUSSEINI, ZAYNA ISHAQ

2013-01-01T23:59:59.000Z

408

Transport-controlled kinetics of dissolution and precipitation...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Transport-controlled kinetics of dissolution and precipitation in the sediments under alkaline and saline conditions . Transport-controlled kinetics of dissolution and...

409

Microscale Electrode Design Using Coupled Kinetic, Thermal and...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling 2010 DOE...

410

Microscale Electrode Design Using Coupled Kinetic, Thermal and...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling 2009 DOE...

411

Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes 2010 DOE...

412

A Comparison of HCCI Engine Performance Data and Kinetic Modeling...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

of HCCI Engine Performance Data and Kinetic Modeling Results over a Wide Rangeof Gasoline Range Surrogate Fuel Blends A Comparison of HCCI Engine Performance Data and Kinetic...

413

Improving Combustion Software to Solve Detailed Chemical Kinetics...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Combustion Software to Solve Detailed Chemical Kinetics for HECC Improving Combustion Software to Solve Detailed Chemical Kinetics for HECC 2012 DOE Hydrogen and Fuel Cells Program...

414

Precision laser aiming system  

DOE Patents [OSTI]

A precision laser aiming system comprises a disrupter tool, a reflector, and a laser fixture. The disrupter tool, the reflector and the laser fixture are configurable for iterative alignment and aiming toward an explosive device threat. The invention enables a disrupter to be quickly and accurately set up, aligned, and aimed in order to render safe or to disrupt a target from a standoff position.

Ahrens, Brandon R. (Albuquerque, NM); Todd, Steven N. (Rio Rancho, NM)

2009-04-28T23:59:59.000Z

415

The effects of early time laser drive on hydrodynamic instability growth in National Ignition Facility implosions  

SciTech Connect (OSTI)

Defects on inertial confinement fusion capsule surfaces can seed hydrodynamic instability growth and adversely affect capsule performance. The dynamics of shocks launched during the early period of x-ray driven National Ignition Facility (NIF) implosions determine whether perturbations will grow inward or outward at peak implosion velocity and final compression. In particular, the strength of the first shock, launched at the beginning of the laser pulse, plays an important role in determining Richtmyer-Meshkov (RM) oscillations on the ablation front. These surface oscillations can couple to the capsule interior through subsequent shocks before experiencing Rayleigh-Taylor (RT) growth. We compare radiation hydrodynamic simulations of NIF implosions to analytic theories of the ablative RM and RT instabilities to illustrate how early time laser strength can alter peak velocity growth. We develop a model that couples the RM and RT implosion phases and captures key features of full simulations. We also show how three key parameters can control the modal demarcation between outward and inward growth.

Peterson, J. L.; Clark, D. S.; Suter, L. J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Masse, L. P. [CEA, DAM, DIF, 91297 Arpajon (France)

2014-09-15T23:59:59.000Z

416

Fusion reactor pumped laser  

DOE Patents [OSTI]

A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam.

Jassby, Daniel L. (Princeton, NJ)

1988-01-01T23:59:59.000Z

417

Fluorinated laser dyes  

DOE Patents [OSTI]

A novel class of dye is disclosed which is particularly efficient and stable for dye laser applications, lasing between 540 and 570 nm.

Hammond, Peter R. (Livermore, CA); Feeman, James F. (Wyomissing, PA)

1992-01-01T23:59:59.000Z

418

ATF CO2 LASER  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

*Operate at low pressure <<1 atm *Bandwidth P (10 atm supports a picosecond pulse) 4 Ultrafast gas lasers require high pressure Inverse Fourier Transform for discrete spectrum...

419

Novel fluorinated laser dyes  

DOE Patents [OSTI]

A novel class of dye is disclosed which is particularly efficient and stable for dye laser applications, lasing between 540 and 570 nm.

Hammond, Peter R. (Livermore, CA); Feeman, James F. (Wyomissing, PA)

1991-01-01T23:59:59.000Z

420

Modeling of Reactor Kinetics and Dynamics  

SciTech Connect (OSTI)

In order to model a full fuel cycle in a nuclear reactor, it is necessary to simulate the short time-scale kinetic behavior of the reactor as well as the long time-scale dynamics that occur with fuel burnup. The former is modeled using the point kinetics equations, while the latter is modeled by coupling fuel burnup equations with the kinetics equations. When the equations are solved simultaneously with a nonlinear equation solver, the end result is a code with the unique capability of modeling transients at any time during a fuel cycle.

Matthew Johnson; Scott Lucas; Pavel Tsvetkov

2010-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Laser Program annual report 1987  

SciTech Connect (OSTI)

This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies.

O'Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W. (eds.)

1989-07-01T23:59:59.000Z

422

Kinetic limits of dynamical systems  

E-Print Network [OSTI]

Since the pioneering work of Maxwell and Boltzmann in the 1860s and 1870s, a major challenge in mathematical physics has been the derivation of macroscopic evolution equations from the fundamental microscopic laws of classical or quantum mechanics. Macroscopic transport equations lie at the heart of many important physical theories, including fluid dynamics, condensed matter theory and nuclear physics. The rigorous derivation of macroscopic transport equations is thus not only a conceptual exercise that establishes their consistency with the fundamental laws of physics: the possibility of finding deviations and corrections to classical evolution equations makes this subject both intellectually exciting and relevant in practical applications. The plan of these lectures is to develop a renormalisation technique that will allow us to derive transport equations for the kinetic limits of two classes of simple dynamical systems, the Lorentz gas and kicked Hamiltonians (or linked twist maps). The technique uses the ergodic theory of flows on homogeneous spaces (homogeneous flows for short), and is based on joint work with Andreas Str\\"ombergsson.

Jens Marklof

2014-08-06T23:59:59.000Z

423

Laser photoelectron spectroscopy of ions  

SciTech Connect (OSTI)

This enterprise uses photoelectron spectroscopy to study the properties of negative ions and radicals. The essence of our experiment is to cross a 0.6 keV mass-selected ion beam (M{sup {minus}}) with the output of a CW laser, {Dirac h}{omega}{sub o}. The resultant detached photoelectrons with kinetic energy, KE, are energy analyzed by means of a set of electrostatic hemispherical analyzers. Analysis of the photoelectron spectra enables us to extract molecular electron affinities, vibrational frequencies and electronic splittings of the final radical, M, as well as the relative molecular geometries of ions (M{sup {minus}}) and radicals (M). We have scrutinized the two simplest nitrenes: methylnitrene (CH{sub 3}N) and phenylnitrene (C{sub 6}H{sub 5}N). By preparing the corresponding anions, CH{sub 3}N{sup {minus}} and C{sub 6}H{sub 5}N{sup {minus}}, we have studied these nitrene biradicals. Singlet methylnitrene is especially interesting since it is formally a transition state.''

Ellison, G.B.

1992-01-16T23:59:59.000Z

424

Kinetic description of mixtures of anisotropic fluids  

E-Print Network [OSTI]

A simple system of coupled kinetic equations for quark and gluon anisotropic systems is solved numerically. The solutions are compared with the predictions of the anisotropic hydrodynamics describing a mixture of anisotropic fluids. We find that the solutions of the kinetic equations can be well reproduced by anisotropic hydrodynamics if the initial distribution are oblate for both quarks and gluons. On the other hand, the solutions of the kinetic equations have a different qualitative behavior from those obtained in anisotropic hydrodynamics if the initial configurations are oblate-prolate or prolate-prolate. This suggests that an extension of the anisotropic hydrodynamics scheme for the mixture of anisotropic fluids is needed, where higher moments of the kinetic equations are used and present simplifications are avoided.

Wojciech Florkowski; Oskar Madetko

2014-02-11T23:59:59.000Z

425

Mechanistic studies using kinetic isotope effects  

E-Print Network [OSTI]

MECHANISTIC STUDIES USING KINETIC ISOTOPE EFFECTS A Thesis by BRIAN E. SCHULMFIER Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requtrements for the degree of MASTER OF SCIENCE December... 1999 Major Subject: Chemistry MECHANISTIC STUDIES USING KINETIC ISOTOPE EFFECTS A Thesis by BRIAN E. SCHULMEIER Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved...

Schulmeier, Brian E.

2012-06-07T23:59:59.000Z

426

Kinetic decoupling of WIMPs: analytic expressions  

E-Print Network [OSTI]

We present a general expression for the values of the average kinetic energy and of the temperature of kinetic decoupling of a WIMP, valid for any cosmological model. We show an example of the usage of our solution when the Hubble rate has a power-law dependence on temperature, and we show results for the specific cases of kination cosmology and low- temperature reheating cosmology.

Visinelli, Luca

2015-01-01T23:59:59.000Z

427

Longitudinal discharge laser electrodes  

DOE Patents [OSTI]

The improved longitudinal discharge laser electrode with IR baffle includes an electrode made up of washers spaced along the laser axis in order to form inter-washer spaces for hollow cathode discharge to take place and for IR radiation to be trapped. Additional IR baffles can be placed between the electrode ann the window. 2 figs.

Warner, B.E.; Miller, J.L.; Ault, E.R.

1994-08-23T23:59:59.000Z

428

Laser beam generating apparatus  

DOE Patents [OSTI]

Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect). 11 figures.

Warner, B.E.; Duncan, D.B.

1993-12-28T23:59:59.000Z

429

Dye laser amplifier  

DOE Patents [OSTI]

An improved dye laser amplifier is disclosed. The efficiency of the dye laser amplifier is increased significantly by increasing the power of a dye beam as it passes from an input window to an output window within the dye chamber, while maintaining the intensity of the dye beam constant. 3 figs.

Moses, E.I.

1992-12-01T23:59:59.000Z

430

Laser beam generating apparatus  

DOE Patents [OSTI]

Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus is described. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect). 7 figures.

Warner, B.E.; Duncan, D.B.

1994-02-15T23:59:59.000Z

431

Laser Programs Highlight 1995  

SciTech Connect (OSTI)

Our contributions to laser science and technology and corresponding applications range from concept to design of the National Ignition Facility, transfer of Atomic Vapor Laser Isotope Separation technology to the private sector, and from new initiatives in industry and defense to micro-optics for improving human vision.

Jacobs, R.R.

1997-01-31T23:59:59.000Z

432

Explosively pumped laser light  

DOE Patents [OSTI]

A single shot laser pumped by detonation of an explosive in a shell casing. The shock wave from detonation of the explosive causes a rare gas to luminesce. The high intensity light from the gas enters a lasing medium, which thereafter outputs a pulse of laser light to disable optical sensors and personnel.

Piltch, Martin S. (Los Alamos, NM); Michelotti, Roy A. (Los Alamos, NM)

1991-01-01T23:59:59.000Z

433

Liquid heat capacity lasers  

DOE Patents [OSTI]

The heat capacity laser concept is extended to systems in which the heat capacity lasing media is a liquid. The laser active liquid is circulated from a reservoir (where the bulk of the media and hence waste heat resides) through a channel so configured for both optical pumping of the media for gain and for light amplification from the resulting gain.

Comaskey, Brian J. (Walnut Creek, CA); Scheibner, Karl F. (Tracy, CA); Ault, Earl R. (Livermore, CA)

2007-05-01T23:59:59.000Z

434

Laser dividing apparatus  

DOE Patents [OSTI]

A laser beam dividing apparatus (10) having a first beam splitter (14) with an aperture (16) therein positioned in the path of a laser beam (12) such that a portion of the laser beam (12) passes through the aperture (16) onto a second beam splitter (20) and a portion of the laser beam (12) impinges upon the first beam splitter (14). Both the first beam splitter (14) and the second beam splitter (20) are, optionally, made from a dichroic material such that a green component (24) of the laser beam (12) is reflected therefrom and a yellow component (26) is refracted therethrough. The first beam splitter (14) and the second beam splitter (20) further each have a plurality of facets (22) such that the components (24, 26) are reflected and refracted in a number equaling the number of facets (22).

English, Jr., R. Edward (Tracy, CA); Johnson, Steve A. (Tracy, CA)

1995-01-01T23:59:59.000Z

435

Laser controlled flame stabilization  

DOE Patents [OSTI]

A method and apparatus is provided for initiating and stabilizing fuel combustion in applications such as gas turbine electrical power generating engines and jet turbine engines where it is desired to burn lean fuel/air mixtures which produce lower amounts of NO.sub.x. A laser induced spark is propagated at a distance from the fuel nozzle with the laser ignitor being remotely located from the high temperature environment of the combustion chamber. A laser initiating spark generated by focusing high peak power laser light to a sufficiently tight laser spot within the fuel to cause the ionization of air and fuel into a plasma is unobtrusive to the flow dynamics of the combustion chamber of a fuel injector, thereby facilitating whatever advantage can be taken of flow dynamics in the design of the fuel injector.

Early, James W. (Los Alamos, NM); Thomas, Matthew E. (Huntsville, AL)

2001-01-01T23:59:59.000Z

436

Catalac free electron laser  

DOE Patents [OSTI]

A catalac free electron laser using a rf linac (catalac) which acts as a catalyst to accelerate an electron beam in an initial pass through the catalac and decelerate the electron beam during a second pass through the catalac. During the second pass through the catalac, energy is extracted from the electron beam and transformed to energy of the accelerating fields of the catalac to increase efficiency of the device. Various embodiments disclose the use of post linacs to add electron beam energy extracted by the wiggler and the use of supplementary catalacs to extract energy at various energy peaks produced by the free electron laser wiggler to further enhance efficiency of the catalac free electron laser. The catalac free electron laser can be used in conjunction with a simple resonator, a ring resonator or as an amplifier in conjunction with a master oscillator laser.

Brau, Charles A. (Los Alamos, NM); Swenson, Donald A. (Los Alamos, NM); Boyd, Jr., Thomas J. (Los Alamos, NM)

1982-01-01T23:59:59.000Z

437

Guest Editorial: Laser Damage  

SciTech Connect (OSTI)

Laser damage of optical materials, first reported in 1964, continues to limit the output energy and power of pulsed and continuous-wave laser systems. In spite of some 48 years of research in this area, interest from the international laser community to laser damage issues remains at a very high level and does not show any sign of decreasing. Moreover, it grows with the development of novel laser systems, for example, ultrafast and short-wavelength lasers that involve new damage effects and specific mechanisms not studied before. This interest is evident from the high level of attendance and presentations at the annual SPIE Laser Damage Symposium (aka, Boulder Damage Symposium) that has been held in Boulder, Colorado, since 1969. This special section of Optical Engineering is the first one devoted to the entire field of laser damage rather than to a specific part. It is prepared in response to growing interest from the international laser-damage community. Some papers in this special section were presented at the Laser Damage Symposium; others were submitted in response to the general call for papers for this special section. The 18 papers compiled into this special section represent many sides of the broad field of laser-damage research. They consider theoretical studies of the fundamental mechanisms of laser damage including laser-driven electron dynamics in solids (O. Brenk and B. Rethfeld; A. Nikiforov, A. Epifanov, and S. Garnov; T. Apostolova et al.), modeling of propagation effects for ultrashort high-intensity laser pulses (J. Gulley), an overview of mechanisms of inclusion-induced damage (M. Koldunov and A. Manenkov), the formation of specific periodic ripples on a metal surface by femtosecond laser pulses (M. Ahsan and M. Lee), and the laser-plasma effects on damage in glass (Y. Li et al). Material characterization is represented by the papers devoted to accurate and reliable measurements of absorption with special emphasis on thin films (C. Mühlig and S. Bublitz; B. Cho, E. Danielewicz, and J. Rudisill; W. Palm et al; and J. Lu et al.). Statistical treatment of measurements of the laser-damage threshold (J. Arenberg) and the relationship to damage mechanisms (F. Wagner et al.) represent the large subfield of laser-damage measurements. Various aspects of multilayer coating and thin-film characterization are considered in papers by B. Cho, J. Rudisill, and E. Danielewicz (spectral shift in multilayer mirrors) and R. Weber et al. (novel approach to damage studies based on third-harmonic generation microscopy). Of special interest for readers is the paper by C. Stolz that summarizes the results of four “thin-film damage competitions” organized as a part of the Laser Damage Symposium. Another paper is devoted to thermal annealing of damage precursors (N. Shen et al.). Finally, the influence of nano-size contamination on initiation of laser damage by ultrashort pulses is considered in paper of V. Komolov et al.

Vitaly Gruzdev, Michelle D. Shinn

2012-12-01T23:59:59.000Z

438

Experimental and Computational Studies of High Energy Density Plasma Streams Ablated from Fine Wires  

SciTech Connect (OSTI)

Experimental and computational studies of high energy density plasma streams ablated from fine wires. Laboratory of Plasma Studies, School of Electrical and Computer Engineering, Cornell University. Principal Investigators: Dr. John B. Greenly and Dr. Charles E. Seyler. This report summarizes progress during the final year of this project to study the physics of high energy density (HED) plasma streams of 10^17-10^20/cm3 density and high velocity (~100-500 km/s). Such streams are produced from 5-250 micrometer diameter wires heated and ionized by a 1 MA, 250 ns current pulse on the COBRA pulsed power facility at Cornell University. Plasma is ablated from the wires and is driven away to high velocity by unbalanced JxB force. A wire, or an array of wires, can persist as an essentially stationary, continuous source of this streaming plasma for >200 ns, even with driving magnetic fields of many Tesla and peak current densities in the plasma of many MA/cm2. At the heart of the ablation stream generation is the continuous transport of mass from the relatively cold, near-solid-density wire "core" into current-carrying plasma within 1 mm of the wire, followed by the magnetic acceleration of that plasma and its trapped flux to form a directed stream. In the first two years of this program, an advancing understanding of ablation physics led to the discovery of several novel wire ablation experimental regimes. In the final year, one of these new HED plasma regimes has been studied in quantitative detail. This regime studies highly reproducible magnetic reconnection in strongly radiating plasma with supersonic and superalfvenic flow, and shock structures in the outflow. The key discovery is that very heavy wires, e.g. 250 micrometer diameter Al or 150 micrometer Cu, behave in a qualitatively different way than the lighter wires typically used in wire-array Z-pinches. Such wires can be configured to produce a static magnetic X-point null geometry that stores magnetic and thermal energy; reconnection and outflow are triggered when the current begins to decrease and the electric field reverses. The reconnecting flow is driven by both magnetic and thermal pressure forces, and it has been found to be possible to vary the configuration so that one or the other dominates. The magnetic null extends into a current sheet that is heated and radiates strongly, with supersonic outflows. This is the first study of reconnection in this HED plasma regime. This compressible, radiative regime, and the triggering mechanism, may be relevant to solar and astrophysical processes. The PERSEUS extended MHD code has been developed for simulation of these phenomena, and will continue to be used and further developed to help interpret and understand experimental results, as well as to guide experimental design. The code is well-suited to simulations of shocks, and includes Hall and electron inertia physics that appear to be of importance in a number of ablation flow regimes, and definitely in the reconnection regime when gradient scales are comparable to the ion inertial scale. During the final year, our graduate student supported by this grant completed a new version of PERSEUS with the finite volume computational scheme replaced by a discontinuous Galerkin method that gives much less diffusive behavior and allows faster run time and higher spatial resolution. Thecode is now being used to study shock structures produced in the outflow region of the reconnection regime.

Greenly, John B. [Cornell University; Seyler, Charles [Cornell University

2014-03-30T23:59:59.000Z

439

E-Print Network 3.0 - ablation predicts outcome Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

- Department of Mechanical and Aerospace Engineering, University of Florida Collection: Engineering ; Chemistry 2 Real-time measurement of ArF excimer laser corneal tissue...

440

Laser irradiation effects on the CdTe/ZnTe quantum dot structure studied by Raman and AFM spectroscopy  

SciTech Connect (OSTI)

Micro-Raman spectroscopy has been applied to investigate the impact of laser irradiation on semiconducting CdTe/ZnTe quantum dots (QDs) structures. A reference sample (without dots) was also studied for comparison. Both samples were grown by molecular beam epitaxy technique on the p-type GaAs substrate. The Raman spectra have been recorded for different time of a laser exposure and for various laser powers. The spectra for both samples exhibit peak related to the localized longitudinal (LO) ZnTe phonon of a wavenumber equal to 210 cm{sup -1}. For the QD sample, a broad band corresponding to the LO CdTe phonon related to the QD-layer appears at a wavenumber of 160 cm{sup -1}. With increasing time of a laser beam exposure and laser power, the spectra get dominated by tellurium-related peaks appearing at wavenumbers around 120 cm{sup -1} and 140 cm{sup -1}. Simultaneously, the ZnTe surface undergoes rising damage, with the formation of Te aggregates at the pinhole edge as reveal atomic force microscopy observations. Local temperature of irradiated region has been estimated from the anti-Stokes/Stokes ratio of the Te modes intensity and it was found to be close or exceeding ZnTe melting point. Thus, the laser damage can be explained by the ablation process.

Zielony, E.; Placzek-Popko, E.; Henrykowski, A.; Gumienny, Z.; Kamyczek, P.; Jacak, J. [Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Nowakowski, P.; Karczewski, G. [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warsaw (Poland)

2012-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Interferometric and schlieren characterization of the plasmas and shock wave dynamics during laser-triggered discharge in atmospheric air  

SciTech Connect (OSTI)

This paper describes our efforts to reveal the underlying physics of laser-triggered discharges in atmospheric air using a Mach-Zehnder interferometer and schlieren photography. Unlike the hemispherical shock waves that are produced by laser ablation, bell-like morphologies are observed during laser-triggered discharges. Phase shifts are recovered from the interferograms at a time of 1000?ns by the 2D fast Fourier transform method, and then the values of the refractive index are deduced using the Abel inversion. An abundance of free electrons is expected near the cathode surface. The schlieren photographs visualize the formation of stagnation layers at ?600?ns in the interaction zones of the laser- and discharge-produced plasmas. Multiple reflected waves are observed at later times with the development of shock wave propagations. Estimations using the Taylor-Sedov self-similar solution indicated that approximately 45.8% and 51.9% of the laser and electrical energies are transferred into the gas flow motions, respectively. Finally, numerical simulations were performed, which successfully reproduced the main features of the experimental observations, and provided valuable insights into the plasma and shock wave dynamics during the laser-triggered discharge.

Wei, Wenfu; Li, Xingwen, E-mail: xwli@mail.xjtu.edu.cn; Wu, Jian; Yang, Zefeng; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)

2014-08-15T23:59:59.000Z

442

Radiofrequency Ablation of Large Renal Angiomyolipoma: Median-Term Follow-Up  

SciTech Connect (OSTI)

Purpose. To study the feasibility of percutaneous radiofrequency ablation (RFA) of large angiomyolipomas (AMLs) using saline-cooled electrodes. Materials and Methods. Institutional Review Board approval for the study was received. Four patients (all female, age range 33-67 years) with large AMLs (maximal axis 6.1-32.4 cm) not suitable for embolotherapy or surgery consented to a trial of RFA. Procedures were performed under computerized tomographic guidance using 14G saline-infused electrodes. Two ablations (diameter 4-7 cm) were undertaken in each patient. Variables studied were technical success, treatment safety, alteration of tumor consistency, tumor size, effect on renal function, and medium-term freedom from haemorrhage. Results. All four patients underwent successful RFA without any intraprocedural complications. There has been no haemorrhage, or new renal specific symptom, during a minimum 48-month period, and normal renal function has been normal. On follow-up radiological imaging, the tumors have become fattier with involution of the soft-tissue elements (soft tissue-to-total tumor ratio decreased mean [range] of 0.26 [0.14-0.48] to 0.17 [0.04-0.34] U; p = 0.04 [paired Student t test]). Further evidence of treatment effect was the development of a capsule around the ablation zone, but there was no change in overall tumor volume (mean [range] 1,120 [118-2,845] to 1150 [90-3,013] ml; p = 1 [paired Student t test]). Conclusion. RFA of large AMLs is technically feasible using saline-infused electrodes. The soft-tissue elements decreased in volume; the tumors become fattier; and there has been no renal haemorrhage during a 48-month period.

Gregory, S. M., E-mail: drstephengregory@gmail.com; Anderson, C. J.; Patel, U. [St. George's Hospital and Medical School, Department of Radiology (United Kingdom)

2013-06-15T23:59:59.000Z

443

Genetic ablation and short-duration inhibition of lipoxygenase results in increased macroautophagy  

SciTech Connect (OSTI)

12/15-lipoxygenase (12/15-LOX) is involved in organelle homeostasis by degrading mitochondria in maturing red blood cells and by eliminating excess peroxisomes in liver. Furthermore, 12/15-LOX contributes to diseases by exacerbating oxidative stress-related injury, notably in stroke. Nonetheless, it is unclear what the consequences are of abolishing 12/15-LOX activity. Mice in which the alox15 gene has been ablated do not show an obvious phenotype, and LOX enzyme inhibition is not overtly detrimental. We show here that liver histology is also unremarkable. However, electron microscopy demonstrated that 12/15-LOX knockout surprisingly leads to increased macroautophagy in the liver. Not only macroautophagy but also mitophagy and pexophagy were increased in hepatocytes, which otherwise showed unaltered fine structure and organelle morphology. These findings were substantiated by immunofluorescence showing significantly increased number of LC3 puncta and by Western blotting demonstrating a significant increase for LC3-II protein in both liver and brain homogenates of 12/15-LOX knockout mice. Inhibition of 12/15-LOX activity by treatment with four structurally different inhibitors had similar effects in cultured HepG2 hepatoma cells and SH-SY5Y neuroblastoma cells with significantly increased autophagy discernable already after 2 hours. Hence, our study reveals a link between ablation or inhibition of 12/15-LOX and stimulation of macroautophagy. The enhanced macroautophagy may be related to the known tissue-protective effects of LOX ablation or inhibition under various diseased conditions caused by oxidative stress and ischemia. This could provide an important cleaning mechanism of cells and tissues to prevent accumulation of damaged mitochondria and other cellular components. - Highlights: • A relationship between lipoxygenases and autophagy is disclosed. • 12/15-lipoxygenase knockout increases autophagy in mice liver and brain. • Lipoxygenase inhibition boosts autophagy in human hepatoma and neuroblastoma cells. • Lipoxygenase knockout or inhibition triggers selective autophagy.

Jang, Insook; Park, Sujin; Cho, Jin Won [Department of Integrated OMICS for Biomedical Science, WCU Program of Graduate School, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Yigitkanli, Kazim; Leyen, Klaus van [Neuroprotection Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129 (United States); Roth, Jürgen, E-mail: jurgen.roth@bluewin.ch [Department of Integrated OMICS for Biomedical Science, WCU Program of Graduate School, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

2014-02-15T23:59:59.000Z

444

Use of High-Frequency Jet Ventilation for Percutaneous Tumor Ablation  

SciTech Connect (OSTI)

PurposeTo report feasibility and potential benefits of high-frequency jet ventilation (HFJV) in tumor ablations techniques in liver, kidney, and lung lesions.MethodsThis prospective study included 51 patients (14 women, mean age 66 years) bearing 66 tumors (56 hepatic, 5 pulmonary, 5 renal tumors) with a median size of 16 ± 8.7 mm, referred for tumor ablation in an intention-to-treat fashion before preoperative anesthesiology visit. Cancellation and complications of HFJV were prospectively recorded. Anesthesia and procedure duration, as well as mean CO{sub 2} capnea, were recorded. When computed tomography guidance was used, 3D spacial coordinates of an anatomical target <2 mm in diameter on 8 slabs of 4 slices of 3.75-mm slice thickness were registered.ResultsHFJV was used in 41 of 51 patients. Of the ten patients who were not candidate for HFJV, two patients had contraindication to HFJV (severe COPD), three had lesions invisible under HFJV requiring deep inspiration apnea for tumor targeting, and five patients could not have HFJV because of unavailability of a trained anesthetic team. No specific complication or hypercapnia related to HFJV were observed despite a mean anesthetic duration of 2 h and ventilation performed in procubitus (n = 4) or lateral decubitus (n = 6). Measured internal target movement was 0.3 mm in x- and y-axis and below the slice thickness of 3.75 mm in the z-axis in 11 patients.ConclusionsHFJV is feasible in 80 % of patients allowing for near immobility of internal organs during liver, kidney, and lung tumor ablation.

Denys, Alban, E-mail: alban.denys@chuv.ch; Lachenal, Yann; Duran, Rafael [Lausanne University Hospital, Department of Radiology and Interventional Radiology (Switzerland); Chollet-Rivier, Madeleine [Lausanne University Hospital, Department of Anesthesiology (Switzerland); Bize, Pierre [Lausanne University Hospital, Department of Radiology and Interventional Radiology (Switzerland)

2013-05-02T23:59:59.000Z

445

The Theta Laser A Low Noise Chirped Pulse Laser  

E-Print Network [OSTI]

The Theta Laser A Low Noise Chirped Pulse Laser Dimitrios Mandridis dmandrid@creol.ucf.edu April 29, 2011 CREOL Affiliates Day 2011 #12;2 Objective: Frequency Swept (FM) Mode-locked Laser · Develop a frequency swept laser, · linear f-sweep, · uniform-intensity, · low noise, · with long-term stability

Van Stryland, Eric

446

22nd IAEA-FEC Kinetic theory of Geodesic Acoustic Modes: ... 1 Kinetic theory of Geodesic Acoustic  

E-Print Network [OSTI]

22nd IAEA-FEC Kinetic theory of Geodesic Acoustic Modes: ... 1 Kinetic theory of Geodesic Acoustic Zonca, Liu Chen and Zhiyong Qiu #12;22nd IAEA-FEC Kinetic theory of Geodesic Acoustic Modes: ... 2 Chen and Zhiyong Qiu #12;22nd IAEA-FEC Kinetic theory of Geodesic Acoustic Modes: ... 3 2 Linear

Zonca, Fulvio

447

Quantum electrodynamics in a laser and the electron laser collision  

E-Print Network [OSTI]

Quantum electrodynamics in a laser is formulated, in which the electron-laser interaction is exactly considered, while the interaction of an electron and a single photon is considered by perturbation. The formulation is applied to the electron-laser collisions. The effect of coherence between photons in the laser is therefore fully considered in these collisions. The possibility of $\\gamma-$ray laser generation by use of this kind of collision is discussed.

Qi-Ren Zhang

2014-08-08T23:59:59.000Z

448

1982 laser program annual report  

SciTech Connect (OSTI)

This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications. (MOW)

Hendricks, C.D.; Grow, G.R. (eds.)

1983-08-01T23:59:59.000Z

449

Ultra-fast laser system  

DOE Patents [OSTI]

A laser system is provided which selectively excites Raman active vibrations in molecules. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and remote sensing.

Dantus, Marcos; Lozovoy, Vadim V

2014-01-21T23:59:59.000Z

450

Laser Plasma Material Interactions  

SciTech Connect (OSTI)

Surface treatment by means of pulsed laser beams in reactive atmospheres is an attractive technique to enhance the surface features, such as corrosion and wear resistance or the hardness. Many carbides and nitrides play an important role for technological applications, requiring the mentioned property improvements. Here we present a new promising fast, flexible and clean technique for a direct laser synthesis of carbide and nitride surface films by short pulsed laser irradiation in reactive atmospheres (e.g. methane, nitrogen). The corresponding material is treated by short intense laser pulses involving plasma formation just above the irradiated surface. Gas-Plasma-Surface reactions lead to a fast incorporation of the gas species into the material and subsequently the desired coating formation if the treatment parameters are chosen properly. A number of laser types have been used for that (Excimer Laser, Nd:YAG, Ti:sapphire, Free Electron Laser) and a number of different nitride and carbide films have been successfully produced. The mechanisms and some examples will be presented for Fe treated in nitrogen and Si irradiated in methane.

Schaaf, Peter; Carpene, Ettore [Universitaet Goettingen, II. Physikalisches Institut, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany)

2004-12-01T23:59:59.000Z

451

7-Gate Kinetic AMPA Model Kinetics to match EPSCs from calyx of Held  

E-Print Network [OSTI]

7-Gate Kinetic AMPA Model · Kinetics to match EPSCs from calyx of Held · Multiple closed, open and EPSC amplitude Bruce Graham Department of Computing Science and Mathematics, University of Stirling, U, including the calyx of Held in the mammalian auditory system. Such depression may be mediated

Graham, Bruce

452

Fiber optic laser rod  

DOE Patents [OSTI]

A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

Erickson, G.F.

1988-04-13T23:59:59.000Z

453

Chemical Kinetic Modeling of Advanced Transportation Fuels  

SciTech Connect (OSTI)

Development of detailed chemical kinetic models for advanced petroleum-based and nonpetroleum based fuels is a difficult challenge because of the hundreds to thousands of different components in these fuels and because some of these fuels contain components that have not been considered in the past. It is important to develop detailed chemical kinetic models for these fuels since the models can be put into engine simulation codes used for optimizing engine design for maximum efficiency and minimal pollutant emissions. For example, these chemistry-enabled engine codes can be used to optimize combustion chamber shape and fuel injection timing. They also allow insight into how the composition of advanced petroleum-based and non-petroleum based fuels affect engine performance characteristics. Additionally, chemical kinetic models can be used separately to interpret important in-cylinder experimental data and gain insight into advanced engine combustion processes such as HCCI and lean burn engines. The objectives are: (1) Develop detailed chemical kinetic reaction models for components of advanced petroleum-based and non-petroleum based fuels. These fuels models include components from vegetable-oil-derived biodiesel, oil-sand derived fuel, alcohol fuels and other advanced bio-based and alternative fuels. (2) Develop detailed chemical kinetic reaction models for mixtures of non-petroleum and petroleum-based components to represent real fuels and lead to efficient reduced combustion models needed for engine modeling codes. (3) Characterize the role of fuel composition on efficiency and pollutant emissions from practical automotive engines.

PItz, W J; Westbrook, C K; Herbinet, O

2009-01-20T23:59:59.000Z

454

Saffman-Taylor fingers with kinetic undercooling  

E-Print Network [OSTI]

The mathematical model of a steadily propagating Saffman-Taylor finger in a Hele-Shaw channel has applications to two-dimensional interacting streamer discharges which are aligned in a periodic array. In the streamer context, the relevant regularisation on the interface is not provided by surface tension, but instead has been postulated to involve a mechanism equivalent to kinetic undercooling, which acts to penalise high velocities and prevent blow-up of the unregularised solution. Previous asymptotic results for the Hele-Shaw finger problem with kinetic undercooling suggest that for a given value of the kinetic undercooling parameter, there is a discrete set of possible finger shapes, each analytic at the nose and occupying a different fraction of the channel width. In the limit in which the kinetic undercooling parameter vanishes, the fraction for each family approaches 1/2, suggesting that this 'selection' of 1/2 by kinetic undercooling is qualitatively similar to the well-known analogue with surface tens...

Gardiner, Bennett P J; Dallaston, Michael C; Moroney, Timothy J

2015-01-01T23:59:59.000Z

455

Extension of high-order harmonic generation cutoff via coherent control of intense few-cycle chirped laser pulses  

E-Print Network [OSTI]

for larger dis- tances. #1;b#2; A second-order split-operator technique in the en- ergy representation, which allows the explicit elimination of undesirable fast-oscillating high-energy components, is used for the efficient time propagation of the wave... potential and the laser field. It then oscil- lates quasifreely driven by the Lorenz force and acquires kinetic energy from the laser field. Lastly, after the laser reverses its direction, the returning electron will emit har- monic photons by radiative...

Carrera, Juan J.; Chu, Shih-I

2007-03-16T23:59:59.000Z

456

Nanostructure evolution in joining of Al and Fe nanoparticles with femtosecond laser irradiation  

SciTech Connect (OSTI)

The joining of Al-Fe nanoparticles (NPs) by femtosecond (fs) laser irradiation is reported in this paper. Fe and Al NPs were deposited on a carbon film in vacuum via fs laser ablation. Particles were then exposed to multiple fs laser pulses at fluences between 0.5 and 1.3?mJ/cm{sup 2}. Transmission Electron Microscopy (TEM) and Electron Diffraction X-ray observations indicate that Al and Fe NPs bond to each other under these conditions. For comparison, bonding of Al to Al and Fe to Fe NPs was also investigated. The nanostructure, as observed using TEM, showed that individual Al NPs were monocrystalline while individual Fe NPs were polycrystalline prior to joining and that these structures are retained after the formation of Al-Al and Fe-Fe NPs. Al-Fe NPs produced by fs laser joining exhibited a mixed amorphous and crystalline phase at the interface. Bonding is suggested to originate from intermixing within a region of high field intensity between particles.

Jiao, Z. [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China); Centre for Advanced Materials Joining, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Huang, H.; Zhou, Y., E-mail: hepeng@hit.edu.cn, E-mail: nzhou@uwaterloo.ca [Centre for Advanced Materials Joining, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Liu, L. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Hu, A. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37916 (United States); Duley, W. [Centre for Advanced Materials Joining, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); He, P., E-mail: hepeng@hit.edu.cn, E-mail: nzhou@uwaterloo.ca [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China)

2014-04-07T23:59:59.000Z

457

Bulk measurement of copper and sodium content in CuIn(0.7)Ga(0.3)Se(2) (CIGS) solar cells with nanosecond pulse length laser induced breakdown spectroscopy (LIBS)  

E-Print Network [OSTI]

In this work, we show that laser induced breakdown spectroscopy (LIBS) with a nanosecond pulse laser can be used to measure the copper and sodium content of CuIn(0.7)Ga(0.3)Se(2) (CIGS) thin film solar cells on molybdenum. This method has four significant advantages over methods currently being employed: the method is inexpensive, measurements can be taken in times on the order of one second, without high vacuum, and at distances up to 5 meters or more. The final two points allow for in-line monitoring of device fabrication in laboratory or industrial environments. Specifically, we report a linear relationship between the copper and sodium spectral lines from LIBS and the atomic fraction of copper and sodium measured via secondary ion mass spectroscopy (SIMS), discuss the ablation process of this material with a nanosecond pulse laser compared to shorter pulse duration lasers, and examine the depth resolution of nanosecond pulse LIBS.

Kowalczyk, Jeremy M D; DeAngelis, Alexander; Kaneshiro, Jess; Mallory, Stewart A; Chang, Yuancheng; Gaillard, Nicolas

2013-01-01T23:59:59.000Z

458

Kinetic effects on robustness of electron magnetohydrodynamic structures  

SciTech Connect (OSTI)

Following recent remarkable progress in the development of high-power short-pulse lasers, exploration is ongoing into hitherto unknown phenomena at fast time scales of electrons, the understanding of which is becoming crucial. For a simplified description of such phenomena, the Electron Magnetohydrodynamics (EMHDs) fluid description is often adopted. For the possibility of electron transport in high-density plasma, exact solutions of the EMHD model in the form of electron vortex currents, together with their associated magnetic fields, have been considered. However, the fluid EMHD model does not incorporate kinetic effects. Here, the finite Larmor radius effects owing to a finite electron temperature on the robustness of the exact EMHD structures are investigated using two-dimensional particle-in-cell simulations. It is found that larger EMHD vortex structures can sustain themselves for long periods, even in high temperature plasma; however, sustaining structures at higher temperatures tends to be difficult. With increasing temperature, electrons with finite Larmor radii become disengaged from the localized region. It is also shown that structures localized in smaller regions are more difficult to sustain. A quantitative criterion in terms of the structure size and Larmor radius has been established by simulations over a wide range of parameters. Finally, we conclude that a structure, larger than about eight times the typical Larmor radius at r=R, could form and exist even under the effects of finite electron temperature.

Hata, M. [Department of Physics, Nagoya University, Nagoya 464-8603 (Japan); Sakagami, H. [Fundamental Physics Simulation Research Division, National Institute for Fusion Science, Toki 509-5292 (Japan); Das, A. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2013-04-15T23:59:59.000Z

459

Charge Diagnostics for Laser Plasma Accelerators  

E-Print Network [OSTI]

Laser plasma accelerator, charge diagnostics, Lanex, ICT,Charge Diagnostics for Laser Plasma Accelerators K .CHARGE DIAGNOSTICS CROSS-CALIBRATIONS WITH LASER PLASMA

Nakamura, K.

2011-01-01T23:59:59.000Z

460

EA-1655: Berkeley Lab Laser Accelerator (BELLA) Laser Acquisition, Installation and Use for Research and Development  

Broader source: Energy.gov [DOE]

Berkeley Lab Laser Accelerator (BELLA) Laser Acquisition, Installation and Use for Research and Development

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Neptunium Binding Kinetics with Arsenazo(III)  

SciTech Connect (OSTI)

This document has been prepared to meet FCR&D level 2 milestone M2FT-14IN0304021, “Report on the results of actinide binding kinetics with aqueous phase complexants” This work was carried out under the auspices of the Thermodynamics and Kinetics of Advanced Separations Systems FCR&D work package. The report details kinetics experiments that were performed to measure rates of aqueous phase complexation for pentavalent neptunium with the chromotropic dye Arsenazo III (AAIII). The studies performed were designed to determine how pH, ionic strength and AAIII concentration may affect the rate of the reaction. A brief comparison with hexavalent neptunium is also made. It was identified that as pH was increased the rate of reaction also increased, however increasing the ionic strength and concentration of AAIII had the opposite effect. Interestingly, the rate of reaction of Np(VI) with AAIII was found to be slower than that of the Np(V) reaction.

Leigh R. Martin; Aaron T. Johnson; Stephen P. Mezyk

2014-08-01T23:59:59.000Z

462

Terahertz quantum cascade lasers  

E-Print Network [OSTI]

The development of the terahertz frequency range has long been impeded by the relative dearth of compact, coherent radiation sources of reasonable power. This thesis details the development of quantum cascade lasers (QCLs) ...

Williams, Benjamin S. (Benjamin Stanford), 1974-

2003-01-01T23:59:59.000Z

463

FREE-ELECTRON LASERS  

E-Print Network [OSTI]

to the electric field of the radiation, this energy-exchangewhere the electric field of the radiation would The energydue to the electric field of the laser radiation, but in

Sessler, A.M.

2008-01-01T23:59:59.000Z

464

Along the Laser Beampath  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

from the master oscillator, amplifiy it more than a billion times, and set its spatial profile before injecting it into the main laser beampath. Photo Number: NIF-1107-1416113...

465

Pulsed Laser Deposition | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

is composed of the following: An electro-polished stainless-steel chamber pumped via a turbo molecular pump and backed by a rotary scroll dry pump An excimer laser (KrF) for...

466

Fusion reactor pumped laser  

DOE Patents [OSTI]

A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam. 10 figs.

Jassby, D.L.

1987-09-04T23:59:59.000Z

467

Laser Plasma Interactions  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

processes. A typical configuration uses a low intensity laser beam (2nd, 3rd, or 4th harmonic of 1054-nm) to probe a plasma volume. The Thomson scattered light is collected by a...